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The Works of Benjamin Franklin, including the Private as well as the Official and Scientific Correspondence, together with the Unmutilated and Correct Version of the Autobiography, compiled and edited by John Bigelow (New York: G.P. Putnam’s Sons, 1904). The Federal Edition in 12 volumes. Vol. II (Letters and Misc. Writings 1735-1753).

Author: Benjamin Franklin
Editor: John Bigelow

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XCIV

TO CADWALLADER COLDEN

Philadelphia, 1 January, 1753.

Dear Sir:—

I have your favor of the third past, with your son’s remarks on the Abbé Nollet’s Letters. I think the experiments and observations are judiciously made and so well expressed that, with your and his leave, I would transmit them to Mr. Collinson for publication. I have repeated all the Abbé’s experiments in vacuo, and find them answer exactly as they should do on my principles, and in the material part quite contrary to what he has related of them; so that he has laid himself extremely open by attempting to impose false accounts of experiments on the world to support his doctrine.

M. Dalibard wrote to me that he was preparing an answer that would be published the beginning of this winter; but as he seems to have been imposed on by the Abbé’s confident assertion, that a charged bottle set down on an electric per se is deprived of its electricity, and in his letter to me attempts to account for it, I doubt he is not yet quite master of the subject to do the business effectually. So I conclude to write a civil letter to the Abbé myself, in which, without resenting any thing in his letters, I shall endeavour to set the disputed matters in so clear a light as to satisfy every one who will take the trouble of reading it. Before I send it home, I shall communicate it to you, and take your friendly advice on it. I set out to-morrow on a journey to Maryland, where I expect to be some weeks, but shall have some leisure when I return. At present I can only add my thanks to your ingenious son, and my hearty wishes of a happy new year to you and him, and all yours. I am, Sir, &c.,

B. Franklin.

P. S.—I wrote to you last post, and sent my paper on the Increase of Mankind. I send the Supplemental Electrical Experiments in several fragments of letters, of which Cave1 has made the most, by printing some of them twice over.

XCV

TO JOHN PERKINS

read at the royal society, june 24, 1756

Philadelphia, 4 February, 1753.

Sir:—

I ought to have written to you long since, in answer to yours of October 16th concerning the water-spout; but business partly, and partly a desire of procuring further information by inquiry among my sea-faring acquaintance, induced me to postpone writing from time to time, till I am now almost ashamed to resume the subject, not knowing but you may have forgot what has been said upon it.

Nothing certainly can be more improving to a searcher into nature than objections judiciously made to his opinion, taken up, perhaps, too hastily; for such objections oblige him to re-study the point, consider every circumstance carefully, compare facts, make experiments, weigh arguments, and be slow in drawing conclusions. And hence a sure advantage results; for he either confirms a truth, before too slightly supported, or discovers an error, and receives instruction from the objector.

In this view I consider the objections and remarks you sent me, and thank you for them sincerely; but how much soever my inclinations lead me to philosophical inquiries, I am so engaged in business, public and private, that those more pleasing pursuits are frequently interrupted, and the chain of thought, necessary to be closely continued in such disquisitions, is so broken and disjointed that it is with difficulty I satisfy myself in any of them; and I am now not much nearer a conclusion in this matter of the spout than when I first read your letter.

Yet, hoping we may in time sift out the truth between us, I will send you my present thoughts, with some observations on your reasons on the accounts in the Transactions, and on other relations I have met with. Perhaps while I am writing some new light may strike me, for I shall now be obliged to consider the subject with a little more attention.

I agree with you that, by means of a vacuum in a whirlwind, water cannot be supposed to rise in large masses to the region of the clouds; for the pressure of the surrounding atmosphere could not force it up in a continued body or column to a much greater height than thirty feet. But if there really is a vacuum in the centre, or near the axis of whirlwinds, then, I think, water may rise in such vacuum to that height, or to a less height, as the vacuum may be less perfect.

I had not read Stuart’s account in the Transactions for many years before the receipt of your letter, and had quite forgot it; but now, on viewing his drafts and considering his descriptions, I think they seem to favor my hypothesis; for he describes and draws columns of water, of various heights, terminating abruptly at the top, exactly as water would do when forced up by the pressure of the atmosphere into an exhausted tube.

I must, however, no longer call it my hypothesis, since I find Stuart had the same thought, though some what obscurely expressed, where he says, “he imagines this phenomenon may be solved by suction (improperly so called), or rather pulsion, as in the application of a cupping-glass to the flesh, the air being first voided by the kindled flax.”

In my paper, I supposed a whirlwind and a spout to be the same thing, and to proceed from the same cause; the only difference between them being that the one passes over land, the other over water. I find also in the Transactions that M. de la Pryme was of the same opinion; for he there describes two spouts, as he calls them, which were seen at different times, at Hatfield, in Yorkshire, whose appearances in the air were the same with those of the spouts at sea, and effects the same with those of real whirlwinds.

Whirlwinds have generally a progressive as well as a circular motion; so had what is called the spout, at Topsham (see the account of it in the Transactions), which also appears, by its effects described, to have been a real whirlwind. Water-spouts have, also, a progressive motion; this is sometimes greater and sometimes less; in some violent, in others barely perceivable. The whirlwind at Warrington continued long in Acrement Close.

Whirlwinds generally arise after calms and great heats; the same is observed of water-spouts, which are therefore most frequent in the warm latitudes. The spout that happened in cold weather, in the Downs, described by Mr. Gordon in the Transactions, was, for that reason, thought extraordinary; but he remarks withal, that the weather, though cold when the spout appeared, was soon after much colder; as we find it, commonly, less warm after a whirlwind.

You agree, that the wind blows every way towards a whirlwind, from a large space round. An intelligent whaleman, of Nantucket, informed me, that three of their vessels, which were out in search of whales, happening to be becalmed, lay in sight of each other, at about a league distance, if I remember right, nearly forming a triangle; after some time a water-spout appeared near the middle of the triangle, when a brisk breeze of wind sprung up, and every vessel made sail; and then it appeared to them all, by the setting of the sails, and the course each vessel stood, that the spout was to the leeward of every one of them; and they all declared it to have been so, when they happened afterwards in company, and came to confer about it. So that in this particular likewise, whirlwinds and water-spouts agree.

But if that which appears a water-spout at sea does sometimes, in its progressive motion, meet with and pass over land, and there produce all the phenomena and effects of a whirlwind, it should thence seem still more evident, that a whirlwind and a spout are the same. I send you herewith a letter from an ingenious physician of my acquaintance, which gives one instance of this, that fell within his observation.

A fluid, moving from all points horizontally toward a centre, must at that centre either ascend or descend. Water being in a tub, if a hole be opened in the middle of the bottom, will flow from all sides to the centre, and there descend in a whirl. But air, flowing on and near the surface of land or water, from all sides towards the centre, must at the centre ascend, the land or water hindering its descent.

If these concentring currents of air be in the upper region, they may indeed descend in the spout or whirlwind; but then, when the united current reached the earth or water, it would spread, and probably blow every way from the centre. There may be whirlwinds of both kinds, but from the commonly observed effects I suspect the rising one to be the most common; when the upper air descends, it is perhaps in a greater body extended wider, as in our thunder-gusts, and without much whirling; and when air descends in a spout or whirlwind, I should rather expect it would press the roof of a house inwards, or force in the tiles, shingles, or thatch, force a boat down into the water, or a piece of timber into the earth, than that it would lift them up and carry them away.

It has so happened that I have not met with any accounts of spouts that certainly descended; I suspect they are not frequent. Please to communicate those you mention. The apparent dropping of a pipe from the clouds towards the earth or sea, I will endeavour to explain hereafter.

The augmentation of the cloud, which, as I am informed, is generally if not always the case during a spout, seems to show an ascent, rather than a descent, of the matter of which such cloud is composed; for a descending spout, one would expect, should diminish a cloud. I own, however, that cold air descending may, by condensing the vapors in a lower region, form and increase clouds; which, I think, is generally the case in our common thunder-gusts, and therefore do not lay great stress on this argument.

Whirlwinds and spouts are not always, though most commonly, in the day time. The terrible whirlwind which damaged a great part of Rome, June 11, 1749, happened in the night of that day. The same was supposed to have been first a spout, for it is said to be beyond doubt, that it gathered in the neighbouring sea, as it could be tracked from Ostia to Rome. I find this in Père Boscovich’s account of it, as abridged in the Monthly Review for December, 1750.

In that account, the whirlwind is said to have appeared as a very black, long, and lofty cloud, discoverable, notwithstanding the darkness of the night, by its continually lightning or emitting flashes on all sides, pushing along with a surprising swiftness, and within three or four feet of the ground. Its general effects on houses were, stripping off the roofs, blowing away chimneys, breaking doors and windows, forcing up the floors, and unpaving the rooms, (some of these effects seem to agree well with a supposed vacuum in the centre of the whirlwind,) and the very rafters of the houses were broken and dispersed, and even hurled against houses at a considerable distance, &c.

It seems, by an expression of Père Boscovich’s, as if the wind blew from all sides towards the whirlwind; for, having carefully observed its effects, he concludes of all whirlwinds, “that their motion is circular, and their action attractive.”

He observes, on a number of histories of whirlwinds, &c., “that a common effect of them is to carry up into the air tiles, stones, and animals themselves, which happened to be in their course, and all kinds of bodies unexceptionably, throwing them to a considerable distance, with great impetuosity.”

Such effects seem to show a rising current of air.

I will endeavour to explain my conceptions of this matter by figures, representing a plan, and an elevation of a spout or whirlwind.

I would only first beg to be allowed two or three positions, mentioned in my former paper.

1. That the lower region of air is often more heated, and so more rarefied, than the upper; consequently, specifically lighter. The coldness of the upper region is manifested by the hail, which sometimes falls from it in a hot day.

2. That heated air may be very moist and yet the moisture so equally diffused and rarefied as not to be visible till colder air mixes with it when it condenses and becomes visible. Thus our breath, invisible in summer, becomes visible in winter.

Now let us suppose a tract of land, or sea, of perhaps sixty miles square, unscreened by clouds, and unfanned by winds, during great part of a summer’s day, or, it may be, for several days successively, till it is violently heated, together with the lower region of air in contact with it, so that the said lower air becomes specifically lighter than the superincumbent higher region of the atmosphere, in which the clouds commonly float; let us suppose, also, that the air surrounding this tract has not been so much heated during those days, and therefore remains heavier. The consequence of this should be, as I conceive, that the heated, lighter air, being pressed on all sides, must ascend, and the heavier descend; and as this rising cannot be in all parts, or the whole area, of the tract at once, for that would leave too extensive a vacuum, the rising will begin precisely in that column that happens to be the lightest or most rarefied; and the warm air will flow horizontally from all points to this column, where the several currents meeting, and joining to rise, a whirl is naturally formed, in the same manner as a whirl is formed in the tub of water, by the descending fluid flowing from all sides of the tub to the hole in the centre.

And as the several currents arrive at this central rising column with a considerable degree of horizontal motion, they cannot suddenly change it to a vertical motion; therefore as they gradually, in approaching the whirl, decline from right to curve or circular lines, so, having joined the whirl, they ascend by a spiral motion, in the same manner as the water descends spirally through the hole in the tub before-mentioned.

Lastly, as the lower air, and nearest the surface, is most rarefied by the heat of the sun, that air is most acted on by the pressure of the surrounding cold and heavy air, which is to take its place; consequently its motion towards the whirl is swiftest, and so the force of the lower part of the whirl, or trump, strongest, and the centrifugal force of its particles greatest; and hence the vacuum round the axis of the whirl should be greatest near the earth or sea, and be gradually diminished as it approaches the region of the clouds, till it ends in a point, as at P, in Figure 2, Plate VI., forming a long and sharp cone.

In Figure 1, which is a plan or ground-plat of a whirlwind, the circle V represents the central vacuum.

Between a a a a and b b b b, I suppose a body of air, condensed strongly by the pressure of the currents moving towards it from all sides without, and by its centrifugal force from within, moving round with prodigious swiftness (having, as it were, the momenta of all the currents, ——> ——> ——> ——>, united in itself), and with a power equal to its swiftness and density.

It is this whirling body of air between a a a a and b b b b that rises spirally; by its force it tears buildings to pieces, twists up great trees by the roots, &c., and by its spiral motion raises the fragments so high, till the pressure of the surrounding and approaching currents, diminishing, can no longer confine them to the circle, or their own centrifugal force, increasing, grows too strong for such pressure, when they fly off in tangent lines, as stones out of a sling, and fall on all sides and at great distances.

If it happens at sea, the water under and between a a a a and b b b b will be violently agitated and driven about, and parts of it raised with the spiral current, and thrown about so as to form a bush-like appearance.

This circle is of various diameters, sometimes very large.

If the vacuum passes over water, the water may rise in it, in a body or column, to near the height of thirty-two feet.

If it passes over houses, it may burst their windows or walls outwards, pluck off the roofs, and pluck up the floors, by the sudden rarefaction of the air contained within such buildings; the outward pressure of the atmosphere being suddenly taken off. So the stopped bottle of air bursts under the exhausted receiver of the air-pump.

Figure 2 is to represent the elevation of a water-spout, wherein I suppose P P P to be the cone, at first a vacuum, till W W, the rising column of water, has filled so much of it; S S S S, the spiral whirl of air, surrounding the vacuum, and continued higher in a close column after the vacuum ends in the point P, till it reaches the cool region of the air. B B, the bush, described by Stuart, surrounding the foot of the column of water.

WATER SPOUT.

Now, I suppose, this whirl of air will, at first, be as invisible as the air itself, though reaching in reality from the water to the region of cool air, in which our low summer thunder-clouds commonly float; but presently it will become visible at its extremities. At its lower end, by the agitation of the water under the whirling part of the circle, between P and S, forming Stuart’s bush, and by the welling and rising of the water in the beginning vacuum, which is at first a small, low, broad cone, whose top gradually rises and sharpens as the force of the whirl increases. At its upper end it becomes visible, by the warm air brought up to the cooler region, where its moisture begins to be condensed into thick vapor by the cold, and is seen first at A, the highest part, which, being now cooled, condenses what rises next at B, which condenses that at C, and that condenses what is rising at D, the cold operating by the contact of the vapors faster in a right line downwards than the vapors themselves can climb in a spiral line upwards; they climb, however, and, as by continual addition they grow denser, and consequently their centrifugal force greater, and being risen above the concentrating currents that compose the whirl, fly off, spread, and form a cloud.

It seems easy to conceive how, by this successive condensation from above, the spout appears to drop or descend from the cloud, though the materials of which it is composed are all the while ascending.

The condensation of the moisture contained in so great a quantity of warm air as may be supposed to rise in a short time in this prodigiously rapid whirl, is, perhaps, sufficient to form a great extent of cloud, though the spout should be over land, as those at Hatfield; and if the land appears not to be very dusty, perhaps the lower part of the spout will scarce become visible at all, though the upper, or what is commonly called the descending, part be very distinctly seen.

The same may happen at sea, in case the whirl is not violent enough to make a high vacuum, and raise the column, &c. In such case, the upper part A B C D only will be visible, and the bush perhaps below.

But if the whirl be strong, and there be much dust on the land, and the column W W be raised from the water, then the lower part becomes visible, and sometimes even united to the upper part. For the dust may be carried up in the spiral whirl, till it reach the region where the vapor is condensed, and rise with that even to the clouds; and the friction of the whirling air, on the sides of the column W W, may detach great quantities of its water, break it into drops, and carry them up in the spiral whirl, mixed with the air; the heavier drops may indeed fly off, and fall in a shower, round the spout; but much of it will be broken into vapor, yet visible; and thus, in both cases, by dust at land, and by water at sea, the whole tube may be darkened and rendered visible.

As the whirl weakens, the tube may (in appearance) separate in the middle, the column of water subsiding, and the superior condensed part drawing up to the cloud. Yet still the tube or whirl of air may remain entire, the middle only becoming invisible, as not containing visible matter.

Dr. Stuart says: “It was observable of all the spouts he saw, but more perceptible of the great one, that towards the end it began to appear like a hollow canal, only black in the borders but white in the middle; and though at first it was altogether black and opake, yet now one could very distinctly perceive the sea water to fly up along the middle of this canal, as smoke up a chimney.”

And Dr. Mather, describing a whirlwind, says: “A thick, dark, small cloud arose, with a pillar of light in it, of about eight or ten feet diameter, and passed along the ground in a tract not wider than a street, horribly tearing up trees by the roots, blowing them up in the air like feathers, and throwing up stones of great weight to a considerable height in the air,” &c.

These accounts, the one of water-spouts, the other of a whirlwind, seem in this particular to agree; what one gentleman describes as a tube, black in the borders and white in the middle, the other calls a black cloud with a pillar of light in it; the latter expression has only a little more of the marvellous, but the thing is the same; and it seems not very difficult to understand. When Dr. Stuart’s spouts were full charged—that is, when the whirling pipe of air was filled between a a a a and b b b b, Figure 1, with quantities of drops, and vapor torn off from the column W W, Figure 2, the whole was rendered so dark as that it could not be seen through, nor the spiral ascending motion discovered; but when the quantity ascending lessened, the pipe became more transparent, and the ascending motion visible. For, by inspection of the figure (Fig. 3) representing a section of our spout, with the vacuum in the middle, it is plain that if we look at such a hollow pipe in the direction of the arrows, and suppose opake particles to be equally mixed in the space between the two circular lines, both the part between the arrows a and b and that between the arrows c and d will appear much darker than that between b and c, as there must be many more of those opake particles in the line of vision across the sides than across the middle. It is thus, that a hair in a microscope evidently appears to be a pipe, the sides showing darker than the middle. Dr. Mather’s whirl was probably filled with dust, the sides were very dark, but the vacuum within rendering the middle more transparent, he calls it a pillar of light.

It was in this more transparent part between b and c that Stuart could see the spiral motion of the vapors, whose lines on the nearest and farthest side of the transparent part crossing each other, represented smoke ascending in a chimney; for, the quantity being still too great in the line of sight through the sides of the tube, the motion could not be discovered there, and so they represented the solid sides of the chimney.

When the vapors reach in the pipe from the clouds near to the earth, it is no wonder now to those who understand electricity, that flashes of lightning should descend by the spout, as in that of Rome.

But you object: If water may be thus carried into the clouds, why have we not salt rains? The objection is strong and reasonable, and I know not whether I can answer it to your satisfaction. I never heard but of one salt rain, and that was where a spout passed pretty near a ship; so I suppose it to be only the drops thrown off from the spout by the centrifugal force (as the birds were at Hatfield), when they had been carried so high as to be above, or to be too strongly centrifugal for the pressure of the concurring winds surrounding it. And indeed I believe there can be no other kind of salt rain; for it has pleased the goodness of God so to order it, that the particles of air will not attract the particles of salt, though they strongly attract water.

Hence, though all metals, even gold, may be united with air, and rendered volatile, salt remains fixed in the fire, and no heat can force it up to any considerable height, or oblige the air to hold it. Hence, when salt rises, as it will a little way, into air with water, there is instantly a separation made; the particles of water adhere to the air, and the particles of salt fall down again, as if repelled and forced off from the water by some power in the air; or as some metals, dissolved in a proper menstruum, will quit the solvent when other matter approaches, and adhere to that, so the water quits the salt and embraces the air, but air will not embrace the salt and quit the water, otherwise our rains would indeed be salt, and every tree and plant on the face of the earth be destroyed, with all the animals that depend on them for subsistence. He who hath proportioned and given proper qualities to all things, was not unmindful of this. Let us adore Him with praise and thanksgiving!

By some accounts of seamen, it seems the column of water, W W, sometimes falls suddenly; and if it be, as some say, fifteen or twenty yards diameter, it must fall with great force, and they may well fear for their ships. By one account, in the Transactions, of a spout that fell at Colne, in Lancashire, one would think the column is sometimes lifted off from the water and carried over land, and there let fall in a body; but this, I suppose, happens rarely.

Stuart describes his spouts as appearing no bigger than a mast, and sometimes less; but they were seen at a league and a half distance.

I think I formerly read in Dampier, or some other voyager, that a spout, in its progressive motion, went over a ship becalmed on the coast of Guinea, and first threw her down on one side, carrying away her foremast, then suddenly whipped her up and threw her down on the other side, carrying away her mizenmast, and the whole was over in an instant. I suppose the first mischief was done by the fore side of the whirl, the latter by the hinder side, their motion being contrary.

I suppose a whirlwind, or spout, may be stationary, when the concurring winds are equal; but if unequal, the whirl acquires a progressive motion, in the direction of the strongest pressure.

When the wind that gives the progressive motion becomes stronger below than above, or above than below, the spout will be bent, and, the cause ceasing, straighten again.

Your queries, towards the end of your paper, appear judicious and worth considering. At present I am not furnished with facts sufficient to make any pertinent answer to them; and this paper has already a sufficient quantity of conjecture.

Your manner of accommodating the accounts to your hypothesis of descending spouts is, I own, ingenious, and perhaps that hypothesis may be true. I will consider it farther; but as yet I am not satisfied with it, though hereafter I may be.

Here you have my method of accounting for the principal phenomena, which I submit to your candid examination.

And as I now seem to have almost written a book instead of a letter, you will think it high time I should conclude, which I beg leave to do, with assuring you that I am, Sir, &c.,

B. Franklin.

XCVI

TO JAMES BOWDOIN

Philadelphia, 28 February, 1753.

Dear Sir:—

The enclosed is a copy of a letter and some papers I received lately from a friend, of which I have struck off fifty copies by the press to distribute among my ingenious acquaintance in North America, hoping some of them will make the observations proposed. The improvement of geography and astronomy is the common concern of all polite nations, and I trust our country will not miss the opportunity of sharing in the honor to be got on this occasion. The French originals are despatched by express overland to Quebec. I doubt not but you will do what may lie in your power to promote the making these observations in New England, and that we may not be excelled by the American French either in diligence or accuracy. We have here a three-foot reflecting telescope and other proper instruments, and intend to observe at our Academy, if the weather permit. You will see by our Almanac that we have had this transit under consideration before the arrival of these French letters.1

Dr. Colden’s book was printed in England last summer, but not to be published till the meeting of Parliament. I have one copy, however, which I purpose shortly to send you.

With great esteem and respect, I am, Sir,

Your most humble servant,

B. Franklin.

XCVII

TO JARED ELIOT

Philadelphia, 12 April, 1753.

Dear Sir:—

I received your favor of March 26th, and thank you for communicating to me the very ingenious letter from your friend, Mr. Todd, with whom, if it may be agreeable to him, I would gladly entertain a correspondence. I shall consider his objections till next post.

I thank you for your hint concerning the word adhesion, which should be defined. When I speak of particles of water adhering to particles of air, I mean not a firm adhesion, but a loose one, like that of a drop of water to the end of an icicle before freezing. The firm adhesion is after it is frozen.

I conceive that the original constituent particles of water are perfectly hard, round, and smooth. If so, there must be interstices, and yet the mass incompressible. A box filled with small shot has many interstices, and the shot may be compressed, because they are not perfectly hard. If they were, the interstices would remain the same, notwithstanding the greatest pressure, and would admit sand, as water admits salt.

Our vessel, named the Argo, is gone for the northwest passage; and the captain has borrowed my Journals of the last voyage, except one volume of a broken set, which I send you. I enclose a letter from our friend, Mr. Collinson, and am promised some speltz, which I shall send per next post.

The Tatler tells us of a girl who was observed to grow suddenly proud, and none could guess the reason, till it came to be known that she had got on a pair of new silk garters. Lest you should be puzzled to guess the cause, when you observe any thing of the kind in me, I think I will not hide my new garters under my petticoats, but take the freedom to show them to you, in a paragraph of our friend Collinson’s last letter, viz.—But I ought to mortify, and not indulge, this vanity; I will not transcribe the paragraph, yet I cannot forbear.

“If any of thy friends,” says Peter, “should take notice that thy head is held a little higher up than formerly, let them know: when the grand monarch of France strictly commands the Abbé Mazéas to write a letter in the politest terms to the Royal Society, to return the King’s thanks and compliments in an express manner to Mr. Franklin of Pennsylvania, for his useful discoveries in electricity, and application of the pointed rods to prevent the terrible effects of thunder-storms, I say, after all this, is not some allowance to be made, if thy crest is a little elevated? There are four letters containing very curious experiments on thy doctrine of points and its verification, which will be printed in the new Transactions. I think, now I have stuck a feather in thy cap, I may be allowed to conclude in wishing thee long to wear it. Thine, P. Collinson.”

On reconsidering this paragraph, I fear I have not so much reason to be proud as the girl had; for a feather in the cap is not so useful a thing, or so serviceable to the wearer, as a pair of good silk garters. The pride of man is very differently gratified; and had his Majesty sent me a marshal’s staff, I think I could scarce have been so proud of it as I am of your esteem, and of subscribing myself, with sincerity, dear Sir,

Your affectionate friend and humble servant,

B. Franklin.

XCVIII

TO JAMES BOWDOIN

Philadelphia, 12 April, 1753.

Sir:—

I have shipped eighteen glass jars in casks well packed, on board Captain Branscombe for Boston; six of them are for you, the rest I understand are for the College. Leaf tin, such as they use in silvering looking-glasses, is best to coat them with; they should be coated to within about four or five inches of the brim. Cut the tin into pieces of the form here represented, and they will comply better with the bellying of the glass; one piece only should be round to cover the bottom; the same shapes will serve the inside. I had not conveniency to coat them for you, and feared to trust anybody else, Mr. Kinnersley being abroad in the West Indies. To make the pieces comply the better, they may be cut in two where the cross lines are. They reach from the top to the edge of the round piece which covers the bottom. I place them in loose rims of scabboard, something like a small sieve, in which they stand very well. If you charge more than one or two together, pray take care how you expose your head to an accidental stroke; for, I can assure you from experience, one is sufficient to knock a stout man down; and I believe a stroke from two or three, in the head, would kill him.

Has Dr. Colden’s new book reached you in Boston? If not, I will send it to you.

With great respect, I am, Sir,

Your most humble servant,

B. Franklin.

P. S.—The glass-maker being from home, I cannot now get the account. The tin is laid on with common paste, made of flour and water boiled together, and the pieces may lap over each other a little.

XCIX

TO WILLIAM SMITH1

Philadelphia, 19 April, 1753.

Sir:—

I received your favor of the 11th instant, with your new piece on Education,2 which I shall carefully peruse, and give you my sentiments of it, as you desire, by next post.

I believe the young gentlemen, your pupils, may be entertained and instructed here in mathematics and philosophy to satisfaction. Mr. Alison,1 who was educated at Glasgow, has been long accustomed to teach the latter, and Mr. Grew2 the former, and I think their pupils make great progress. Mr. Alison has the care of the Latin and Greek school; but as he has now three good assistants,3 he can very well afford some hours every day for the instruction of those who are engaged in higher studies. The mathematical school is pretty well furnished with instruments. The English Library is a good one, and we have, belonging to it, a middling apparatus for experimental philosophy, and purpose speedily to complete it. The Loganian Library, one of the best collections in America, will shortly be opened; so that neither books nor instruments will be wanting; and as we are determined always to give good salaries, we have reason to believe we may have always an opportunity of choosing good masters; upon which, indeed, the success of the whole depends. We are obliged to you for your kind offers in this respect, and when you are settled in England we may occasionally make use of your friendship and judgment.

If it suits your convenience to visit Philadelphia before your return to Europe, I shall be extremely glad to see and converse with you here, as well as to correspond with you after your settlement in England. For an acquaintance and communication with men of learning, virtue, and public spirit is one of my greatest enjoyments.

I do not know whether you ever happened to see the first proposals I made for erecting this Academy. I send them enclosed. They had, however imperfect, the desired success, being followed by a subscription of four thousand pounds towards carrying them into execution. And as we are fond of receiving advice, and are daily improving by experience, I am in hopes we shall, in a few years, see a perfect institution. I am, very respectfully, &c.,

B. Franklin.

C

TO WILLIAM SMITH

Philadelphia, 3 May, 1753.

Sir:—

Mr. Peters has just now been with me, and we have compared notes on your new piece. We find nothing in the scheme of education, however excellent, but what is, in our opinion, very practicable. The great difficulty will be to find the Aratus1 and other suitable persons to carry it into execution; but such may be had if proper encouragement be given. We have both received great pleasure in the perusal of it. For my part, I know not when I have read a piece that has more affected me; so noble and just are the sentiments, so warm and animated the language, yet, as censure from your friends may be of more use, as well as more agreeable, to you than praise, I ought to mention that I wish you had omitted, not only the quotation from the Review,1 which you are now justly dissatisfied with, but those expressions of resentment against your adversaries, in pages 65 and 79. In such cases, the noblest victory is obtained by neglect and by shining on.

Mr. Allen has been out of town these ten days, but before he went he directed me to procure him six copies of your piece. Mr. Peters has taken ten. He purposed to have written to you, but omits it, as he expects so soon to have the pleasure of seeing you here. He desires me to present his affectionate compliments to you, and to assure you that you will be very welcome to him. I shall only say that you may depend on my doing all in my power to make your visit to Philadelphia agreeable to you. I am, &c.,

B. Franklin.

CI

TO PETER COLLINSON

Philadelphia, 9 May, 1753.

Sir:—

I thank you for the kind and judicious remarks you have made on my little piece. I have often observed with wonder that temper of the poorer English laborers which you mention, and acknowledge it to be pretty general. When any of them happen to come here, where labor is much better paid than in England, their industry seems to diminish in equal proportion. But it is not so with the German laborers; they retain the habitual industry and frugality they bring with them, and receiving higher wages, an accumulation arises that makes them all rich. When I consider that the English are the offspring of Germans; that the climate they live in is much of the same temperature, and when I see nothing in nature that should create this difference, I am tempted to suspect it must arise from the constitution; and I have sometimes doubted whether the laws peculiar to England, which compel the rich to maintain the poor, have not given the latter a dependence that very much lessens the care of providing against the wants of old age.

I have heard it remarked that the poor in Protestant countries, on the continent of Europe, are generally more industrious than those of Popish countries. May not the more numerous foundations in the latter for relief of the poor have some effect towards rendering them less provident? To relieve the misfortunes of our fellow creatures is concurring with the Deity; it is godlike; but if we provide encouragement for laziness, and support for folly, may we not be found fighting against the order of God and nature, which perhaps has appointed want and misery as the proper punishments for, and cautions against, as well as necessary consequences of, idleness and extravagance? Whenever we attempt to amend the scheme of Providence, and to interfere with the government of the world, we had need be very circumspect, lest we do more harm than good. In New England they once thought blackbirds useless, and mischievous to the corn. They made efforts to destroy them. The consequence was, the blackbirds were diminished; but a kind of worm, which devoured their grass, and which the blackbirds used to feed on, increased prodigiously; then, finding their loss in grass much greater than their saving in corn, they wished again for their blackbirds.

We had here some years since a Transylvanian Tartar, who had travelled much in the East, and came hither merely to see the West, intending to go home through the Spanish West Indies, China, &c. He asked me one day, what I thought might be the reason that so many and such numerous nations, as the Tartars in Europe and Asia, the Indians in America, and the Negroes in Africa, continued a wandering, careless life, and refused to live in cities, and cultivate the arts they saw practised by the civilized parts of mankind? While I was considering what answer to make him he said, in his broken English: “God make man for Paradise. He make him for live lazy. Man make God angry. God turn him out of Paradise, and bid workee. Man no love workee; he want to go to Paradise again; he want to live lazy. So all mankind love lazy.” However this may be, it seems certain that the hope of becoming at some time of life free from the necessity of care and labor, together with fear of penury, are the main springs of most people’s industry. To those, indeed, who have been educated in elegant plenty, even the provision made for the poor may appear misery; but to those who have scarce ever been better provided for, such provision may seem quite good and sufficient. These latter, then, have nothing to fear worse than their present condition, and scarce hope for any thing better than a parish maintenance. So that there is only the difficulty of getting that maintenance allowed while they are able to work, or a little shame they suppose attending it, that can induce them to work at all; and what they do will only be from hand to mouth.

The proneness of human nature to a life of ease, of freedom from care and labor, appears strongly in the little success that has hitherto attended every attempt to civilize our American Indians. In their present way of living, almost all their wants are supplied by the spontaneous productions of nature, with the addition of very little labor, if hunting and fishing may indeed be called labor, where game is so plenty. They visit us frequently, and see the advantages that arts, sciences, and compact societies procure us. They are not deficient in natural understanding; and yet they have never shown any inclination to change their manner of life for ours, or to learn any of our arts. When an Indian child has been brought up among us, taught our language, and habituated to our customs, yet if he goes to see his relatives, and makes one Indian ramble with them, there is no persuading him ever to return. And that this is not natural to them merely as Indians, but as men, is plain from this, that when white persons, of either sex, have been taken prisoners by the Indians, and lived awhile with them, though ransomed by their friends, and treated with all imaginable tenderness to prevail with them to stay among the English, yet in a short time they become disgusted with our manner of life, and the care and pains that are necessary to support it, and take the first opportunity of escaping again into the woods, from whence there is no redeeming them. One instance I remember to have heard, where the person was brought home to possess a good estate; but, finding some care necessary to keep it together, he relinquished it to a younger brother, reserving to himself nothing but a gun and a match-coat, with which he took his way again into the wilderness.

So that I am apt to imagine that close societies, subsisting by labor and art, arose first not from choice but from necessity, when numbers being driven by war from their hunting grounds, and prevented by seas, or by other nations, from obtaining other hunting grounds, were crowded together into some narrow territories, which without labor could not afford them food. However, as matters now stand with us, care and industry seem absolutely necessary to our well-being. They should therefore have every encouragement we can invent, and not one motive to diligence be subtracted; and the support of the poor should not be by maintaining them in idleness, but by employing them in some kind of labor suited to their abilities of body, as I am informed begins to be of late the practice in many parts of England, where workhouses are erected for that purpose. If these were general, I should think the poor would be more careful, and work voluntarily to lay up something for themselves against a rainy day, rather than run the risk of being obliged to work at the pleasure of others for a bare subsistence, and that too under confinement.

The little value Indians set on what we prize so highly, under the name of learning, appears from a pleasant passage that happened some years since, at a treaty between some colonies and the Six Nations. When every thing had been settled to the satisfaction of both sides, and nothing remained but a mutual exchange of civilities, the English Commissioners told the Indians that they had in their country a college for the instruction of youth, who were there taught various languages, arts, and sciences; that there was a particular foundation in favor of the Indians to defray the expense of the education of any of their sons who should desire to take the benefit of it; and said, if the Indians would accept the offer, the English would take half a dozen of their brightest lads, and bring them up in the best manner. The Indians, after consulting on the proposals, replied, that it was remembered that some of their youths had formerly been educated at that college, but that it had been observed that for a long time after they returned to their friends they were absolutely good for nothing; being neither acquainted with the true method of killing deer, catching beavers, or surprising an enemy. The proposition they looked on, however, as a mark of kindness and good will of the English to the Indian nations, which merited a grateful return; and therefore, if the English gentlemen would send a dozen or two of their children to Onondaga, the Great Council would take care of their education, bring them up in what was really the best manner, and make men of them.

I am perfectly of your mind, that measures of great temper are necessary with the Germans; and am not without apprehensions, that, through their indiscretion, or ours, or both, great disorders may one day arise among us. Those who come hither are generally the most stupid of their own nation, and, as ignorance is often attended with credulity when knavery would mislead it, and with suspicion when honesty would set it right; and as few of the English understand the German language, and so cannot address them either from the press or the pulpit, it is almost impossible to remove any prejudices they may entertain. Their clergy have very little influence on the people, who seem to take a pleasure in abusing and discharging the minister on every trivial occasion. Not being used to liberty, they know not how to make a modest use of it. And as Kolben says of the young Hottentots, that they are not esteemed men until they have shown their manhood by beating their mothers, so these seem not to think themselves free, till they can feel their liberty in abusing and insulting their teachers. Thus they are under no restraint from ecclesiastical government; they behave, however, submissively enough at present to the civil government, which I wish they may continue to do, for I remember when they modestly declined intermeddling in our elections, but now they come in droves and carry all before them, except in one or two counties.

Few of their children in the country know English. They import many books from Germany; and of the six printing-houses in the province, two are entirely German, two half German half English, and but two entirely English. They have one German newspaper, and one half-German. Advertisements, intended to be general, are now printed in Dutch and English. The signs in our streets have inscriptions in both languages, and in some places only German. They begin of late to make all their bonds and other legal instruments in their own language, which (though I think it ought not to be) are allowed good in our courts, where the German business so increases that there is continued need of interpreters; and I suppose in a few years they will also be necessary in the Assembly, to tell one half of our legislators what the other half say.

In short, unless the stream of their importation could be turned from this to other colonies, as you very judiciously propose, they will soon so outnumber us that all the advantages we have will, in my opinion, be not able to preserve our language, and even our government will become precarious. The French, who watch all advantages, are now themselves making a German settlement, back of us, in the Illinois country, and by means of these Germans they may in time come to an understanding with ours; and, indeed, in the last war, our Germans showed a general disposition, that seemed to bode us no good. For, when the English, who were not Quakers, alarmed by the danger arising from the defenceless state of our country, entered unanimously into an association, and within this government and the Lower Counties raised, armed, and disciplined near ten thousand men, the Germans, except a very few in proportion to their number, refused to engage in it, giving out, one amongst another, and even in print, that, if they were quiet, the French, should they take the country, would not molest them; at the same time abusing the Philadelphians for fitting out privateers against the enemy, and representing the trouble, hazard, and expense of defending the province, as a greater inconvenience than any that might be expected from a change of government. Yet I am not for refusing to admit them entirely into our colonies. All that seems to me necessary is, to distribute them more equally, mix them with the English, establish English schools where they are now too thick settled, and take some care to prevent the practice, lately fallen into by some of the ship-owners, of sweeping the German gaols to make up the number of their passengers. I say I am not against the admission of Germans in general, for they have their virtues. Their industry and frugality are exemplary. They are excellent husbandmen, and contribute greatly to the improvement of a country.

I pray God to preserve long to Great Britain the English laws, manners, liberties, and religion. Notwithstanding the complaints so frequent in your public papers, of the prevailing corruption and degeneracy of the people, I know you have a great deal of virtue still subsisting among you; and I hope the constitution is not so near a dissolution as some seem to apprehend. I do not think you are generally become such slaves to your vices, as to draw down the justice Milton speaks of, when he says, that——1

CII

TO PETER COLLINSON

the sea and lightning

Philadelphia, — September, 1753.

Sir:—

In my former paper on this subject, written first in 1747, enlarged and sent to England in 1749, I considered the sea as the grand source of lightning, imagining its luminous appearance to be owing to electric fire, produced by friction between the particles of water and those of salt.

Living far from the sea, I had then no opportunity of making experiments on the sea water, and so embraced this opinion too hastily. For, in 1750 and 1751, being occasionally on the seacoast, I found, by experiments, that sea water in a bottle, though at first it would by agitation appear luminous, yet in a few hours it lost that virtue; hence and from this, that I could not by agitating a solution of sea salt in water produce any light, I first began to doubt of my former hypothesis, and to suspect that the luminous appearance in sea water must be owing to some other principles.

I then considered whether it were not possible that the particles of air, being electrics per se, might, in hard gales of wind, by their friction against trees, hills, buildings, &c., as so many minute electric globes, rubbing against non-electric cushions, draw the electric fire from the earth, and that the rising vapors might receive that power from the air, and by such means the clouds become electrified.

If this were so, I imagined that by forcing a constant violent stream of air against my prime conductor, by bellows, I should electrify it negatively; the rubbing particles of air drawing from it part of its natural quantity of the electric fluid. I accordingly made the experiment, but it did not succeed.

In September, 1752, I erected an iron rod to draw the lightning down into my house, in order to make some experiments on it, with two bells to give notice when the rod should be electrified; a contrivance obvious to every electrician.

I found the bells rang sometimes when there was no lightning or thunder, but only a dark cloud over the rod; that sometimes, after a flash of lightning they would suddenly stop; and, at other times, when they had not rung before, they would, after a flash, suddenly begin to ring; that the electricity was sometimes very faint, so that, when a small spark was obtained, another could not be got for some time after; at other times the sparks would follow extremely quick, and once I had a continual stream from bell to bell, the size of a crow-quill; even during the same gust there were considerable variations.

In the winter following I conceived an experiment, to try whether the clouds were electrified positively or negatively; but my pointed rod, with its apparatus, becoming out of order, I did not refit it till towards the spring, when I expected the warm weather would bring on more frequent thunder-clouds.

The experiment was this; to take two phials; charge one of them with lightning from the iron rod, and give the other an equal charge by the electric glass globe, through the prime conductor; when charged, to place them on a table within three or four inches of each other, a small cork ball being suspended by a fine silk thread from the ceiling so as it might play between the wires. If both bottles then were electrified positively, the ball, being attracted and repelled by one, must be also repelled by the other. If the one positively, and the other negatively, then the ball would be attracted and repelled alternately by each, and continue to play between them as long as any considerable charge remained.

Being very intent on making this experiment, it was no small mortification to me that I happened to be abroad during two of the greatest thunder-storms we had early in the spring; and though I had given orders in the family that if the bells rang when I was from home they should catch some of the lightning for me in electrical phials, and they did so, yet it was mostly dissipated before my return; and in some of the other gusts, the quantity of lightning I was able to obtain was so small, and the charge so weak, that I could not satisfy myself; yet I sometimes saw what heightened my suspicions and inflamed my curiosity.

At last, on the 12th of April, 1753, there being a smart gust of some continuance, I charged one phial pretty well with lightning, and the other equally, as near as I could judge, with electricity from my glass globe; and, having placed them properly, I beheld, with great surprise and pleasure, the cork ball play briskly between them, and was convinced that one bottle was electrized negatively.

I repeated this experiment several times during the gust, and in eight succeeding gusts, always with the same success; and being of opinion (for reasons I formerly gave in my letter to Mr. Kinnersley, since printed in London), that the glass globe electrizes positively, I concluded that the clouds are always electrized negatively, or have always in them less than their natural quantity of the electric fluid.

Yet, notwithstanding so many experiments, it seems I concluded too soon; for at last, June the 6th, in a gust which continued from five o’clock P.M., to seven, I met with one cloud that was electrized positively, though several that passed over my rod before, during the same gust, were in the negative state. This was thus discovered.

I had another concurring experiment, which I often repeated, to prove the negative state of the clouds, viz., while the bells were ringing, I took the phial, charged from the glass globe, and applied its wire to the erected rod, considering that if the clouds were electrized positively, the rod, which received its electricity from them, must be so too; and then the additional positive electricity of the phial would make the bells ring faster; but if the clouds were in a negative state, they must exhaust the electric fluid from my rod, and bring that into the same negative state with themselves, and then the wire of a positively charged phial, supplying the rod with what is wanted (which it was obliged otherwise to draw from the earth by means of the pendulous brass ball playing between the two bells), the ringing would cease till the bottle was discharged.

In this manner I quite discharged into the rod several phials, that were charged from the glass globe, the electric fluid streaming from the wire to the rod, till the wire would receive no spark from the finger; and during this supply to the rod from the phial, the bells stopped ringing; but by continuing the application of the phial wire to the rod, I exhausted the natural quantity from the inside surface of the same phials, or, as I call it, charged them negatively.

At length, while I was charging a phial by my glass globe, to repeat the experiment, my bells of themselves stopped ringing, and, after some pause, began to ring again. But now, when I approached the wire of the charged phial to the rod, instead of the usual stream that I expected from the wire to the rod, there was no spark—not even when I brought the wire and the rod to touch; yet the bells continued ringing vigorously, which proved to me that the rod was then positively electrified, as well as the wire of the phial, and equally so; and, consequently, that the particular cloud then over the rod was in the same positive state. This was near the end of the gust.

But this was a single experiment, which, however, destroys my first too general conclusion, and reduces me to this: That the clouds of a thunder-gust are most commonly in a negative state of electricity, but sometimes in a positive state.

The latter I believe is rare; for, though I, soon after the last experiment, set out on a journey to Boston, and was from home most part of the summer, which prevented my making further trials and observations, yet Mr. Kinnersley, returning from the Islands just as I left home, pursued the experiments during my absence, and informs me that he always found the clouds in the negative state.

So that, for the most part, in thunder-strokes, it is the earth that strikes into the clouds, and not the clouds that strike into the earth.

Those who are versed in electric experiments will easily conceive that the effects and appearances must be nearly the same in either case: the same explosion and the same flash between one cloud and another, and between the clouds and mountains, &c.; the same rending of trees, walls, &c., which the electric fluid meets with in its passage; and the same fatal shock to animal bodies; and that pointed rods fixed on buildings or masts of ships, and communicating with the earth or sea, must be of the same service in restoring the equilibrium silently between the earth and clouds, or in conducting a flash or stroke, if one should be, so as to save harmless the house or vessel; for points have equal power to throw off, as to draw on, the electric fire, and rods will conduct up as well as down.

But though the light gained from these experiments makes no alteration in the practice, it makes a considerable one in the theory. And now we as much need an hypothesis to explain by what means the clouds become negatively, as before to show how they become positively, electrified.

I cannot forbear venturing some few conjectures on this occasion; they are what occur to me at present, and though future discoveries should prove them not wholly right, yet they may in the meantime be of some use, by stirring up the curious to make more experiments, and occasion more exact disquisitions.

I conceive, then, that this globe of earth and water, with its plants, animals, and buildings, have, diffused throughout their substance, a quantity of the electric fluid, just as much as they can contain, which I call the natural quantity.

That this natural quantity is not the same in all kinds of common matter under the same dimensions, nor in the same kind of common matter in all circumstances; but a solid foot, for instance, of one kind of common matter may contain more of the electric fluid than a solid foot of some other kind of common matter; and a pound weight of the same kind of common matter may, when in a rarer state, contain more of the electric fluid than when in a denser state.

For the electric fluid being attracted by any portion of common matter, the parts of that fluid (which have among themselves a mutual repulsion) are brought so near to each other, by the attraction of the common matter that absorbs them, as that their repulsion is equal to the condensing power of attraction in common matter; and then such portion of common matter will absorb no more.

Bodies of different kinds, having thus attracted and absorbed what I call their natural quantity, that is, just as much of the electric fluid as is suited to their circumstances of density, rarity, and power of attracting, do not then show any signs of electricity among each other.

And if more electric fluid be added to one of these bodies, it does not enter, but spreads on the surface, forming an atmosphere; and then such body shows signs of electricity.

I have, in a former paper, compared common matter to a sponge, and the electric fluid to water; I beg leave once more to make use of the same comparison, to illustrate farther my meaning in this particular.

When a sponge is somewhat condensed by being squeezed between the fingers, it will not receive and retain so much water as when in its more loose and open state.

If more squeezed and condensed, some of the water will come out of its inner parts, and flow on the surface.

If the pressure of the fingers be entirely removed, the sponge will not only resume what was lately forced out, but attract an additional quantity.

As the sponge in its rarer state will naturally attract and absorb more water, and in its denser state will naturally attract and absorb less water, we may call the quantity it attracts and absorbs in either state its natural quantity, the state being considered.

Now what the sponge is to water, the same is water to the electric fluid.

When a portion of water is in its common dense state, it can hold no more electric fluid than it has; if any be added, it spreads on the surface.

When the same portion of water is rarefied into vapor, and forms a cloud, it is then capable of receiving and absorbing a much greater quantity; there is room for each particle to have an electric atmosphere.

Thus water, in its rarefied state, or in the form of a cloud, will be in a negative state of electricity; it will have less than its natural quantity—that is, less than it is naturally capable of attracting and absorbing in that state.

Such a cloud, then, coming so near the earth as to be within the striking distance, will receive from the earth a flash of the electric fluid, which flash, to supply a great extent of cloud, must sometimes contain a very great quantity of that fluid.

Or such a cloud, passing over woods of tall trees, may, from the points and sharp edges of their moist top leaves, receive silently some supply.

A cloud, being by any means supplied from the earth, may strike into other clouds that have not been supplied, or not so much supplied; and those to others, till an equilibrium is produced among all the clouds that are within striking distance of each other.

The cloud thus supplied, having parted with much of what it first received, may require and receive a fresh supply from the earth, or from some other cloud which by the wind is brought into such a situation as to receive it more readily from the earth.

Hence repeated and continual strokes and flashes, till the clouds have all got nearly their natural quantity as clouds, or till they have descended in showers, and are united again with this terraqueous globe, their original.

Thus thunder-clouds are generally in a negative state of electricity compared with the earth, agreeable to most of our experiments; yet, as by one experiment we found a cloud electrized positively, I conjecture that in that case such cloud, after having received what was, in its rare state, only its natural quantity, became compressed by the driving winds, or some other means, so that part of what it had absorbed was forced out, and formed an electric atmosphere around it in its denser state. Hence it was capable of communicating positive electricity to my rod.

To show that a body in different circumstances of dilatation and contraction is capable of receiving and retaining more or less of the electric fluid on its surface, I would relate the following experiment: I placed a clean wine-glass on the floor, and on it a small silver can. In the can I put about three yards of brass chain; to one end of which I fastened a silk thread, which went right up to the ceiling, where it passed over a pulley, and came down again to my hand, that I might at pleasure draw the chain up out of the can, extending it till within a foot of the ceiling, and let it gradually sink into the can again. From the ceiling, by another thread of fine raw silk, I suspended a small light lock of cotton, so as that when it hung perpendicularly it came in contact with the side of the can. Then, approaching the wire of a charged phial to the can, I gave it a spark which flowed round in an electric atmosphere; and the lock of cotton was repelled from the side of the can to the distance of about nine or ten inches. The can would not then receive another spark from the wire of the phial; but as I gradually drew up the chain, the atmosphere of the can diminished by flowing over the rising chain, and the lock of cotton accordingly drew nearer and nearer to the can; and then, if I again brought the phial wire near the can, it would receive another spark, and the cotton fly off again to its first distance; and thus, as the chain was drawn higher, the can would receive more sparks; because the can and extended chain were capable of supporting a greater atmosphere than the can with the chain gathered up into its belly. And that the atmosphere round the can was diminished by raising the chain, and increased again by lowering, is not only agreeable to reason, since the atmosphere of the chain must be drawn from that of the can, when it rose, and returned to it again when it fell; but was also evident to the eye, the lock of cotton always approaching the can when the chain was drawn up, and receding when it was let down again.

Thus we see that increase of surface makes a body capable of receiving a greater electric atmosphere; but this experiment does not, I own, fully demonstrate my new hypothesis; for the brass and silver still continue in their solid state, and are not rarefied into vapor, as the water is in clouds. Perhaps some future experiments on vaporized water may set this matter in a clearer light.

One seemingly material objection arises to the new hypothesis, and it is this: if water in its rarefied state, as a cloud, requires and will absorb more of the electric fluid than when in its dense state as water, why does it not require from the earth all its wants at the instant of its leaving the surface, while it is yet near, and but just rising in vapor? To this difficulty I own I cannot at present give a solution satisfactory to myself. I thought, however, that I ought to state it in its full force, as I have done, and submit the whole to examination.

And I would beg leave to recommend it to the curious in this branch of natural philosophy, to repeat with care and accurate observation, the experiments I have reported in this and former papers relating to positive and negative electricity, with such other relative ones as shall occur to them, that it may be certainly known whether the electricity communicated by a glass globe be really positive. And also I would request all who may have the opportunity of observing the recent effects of lightning on buildings, trees, &c., that they would consider them particularly with a view to discover the direction. But in these examinations this one thing is always to be understood, viz., that a stream of the electric fluid passing through wood, brick, metal, &c., while such fluid passes in small quantity, the mutually repulsive power of its parts is confined and overcome by the cohesion of the parts of the body it passes through, so as to prevent an explosion; but when the fluid comes in a quantity too great to be confined by such cohesion, it explodes, and rends or fuses the body that endeavoured to confine it. If it be wood, brick, stone, or the like, the splinters will fly off on that side where there is least resistance. And thus, when a hole is struck through pasteboard by the electrified jar, if the surfaces of the pasteboard are not confined or compressed, there will be a bur raised all round the hole on both sides the pasteboard; but if one side be confined, so that the bur cannot be raised on that side, it will be all raised on the other, which way soever the fluid was directed. For the bur round the outside of the hole is the effect of the explosion every way from the centre of the stream, and not an effect of the direction.

In every stroke of lightning, I am of opinion that the stream of the electric fluid, moving to restore the equilibrium between the cloud and the earth, does always previously find its passage, and mark out, as I may say, its own course, taking in its way all the conductors it can find, such as metals, damp walls, moist wood, &c., and will go considerably out of a direct course for the sake of the assistance of good conductors; and that, in this course, it is actually moving, though silently and imperceptibly, before the explosion, in and among the conductors; which explosion happens only when the conductors cannot discharge it as fast as they receive it, by reason of their being incomplete, disunited, too small, or not of the best materials for conducting. Metalline rods, therefore, of sufficient thickness, and extending from the highest part of an edifice to the ground, being of the best materials and complete conductors, will, I think, secure the building from damage, either by restoring the equilibrium so fast as to prevent a stroke, or by conducting it in the substance of the rod as far as the rod goes, so that there shall be no explosion but what is above its point, between that and the clouds.

If it be asked, What thickness of a metalline rod may be supposed sufficient? in answer, I would remark, that five large glass jars, such as I have described in my former papers, discharge a very great quantity of electricity, which, nevertheless, will be all conducted round the corner of a book, by the fine filleting of gold on the cover, it following the gold the farthest way about rather than take the shorter course through the cover, that not being so good a conductor. Now, in this line of gold, the metal is so extremely thin as to be little more than the color of gold, and on an octavo book is not in the whole an inch square, and, therefore, not the thirty-sixth part of a grain, according to M. Réaumur; yet it is sufficient to conduct the charge of five large jars, and how many more I know not. Now, I suppose a wire of a quarter of an inch diameter, to contain about five thousand times as much metal as there is in that gold line; and, if so, it will conduct the charge of twenty-five thousand such glass jars, which is a quantity, I imagine, far beyond what was ever contained in any one stroke of natural lightning. But a rod of half an inch diameter would conduct four times as much as one of a quarter.

And with regard to conducting, though a certain thickness of metal be required to conduct a great quantity of electricity, and at the same time keep its own substance firm and unseparated, and a less quantity, as a very small wire, for instance, will be destroyed by the explosion; yet such small wire will have answered the end of conducting that stroke, though it become incapable of conducting another. And, considering the extreme rapidity with which the electric fluid moves without exploding, when it has a free passage, or complete metal communication, I should think a vast quantity would be conducted in a short time, either to or from a cloud, to restore its equilibrium with the earth, by means of a very small wire, and, therefore, thick rods should seem not so necessary. However, as the quantity of lightning discharged in one stroke cannot well be measured, and in different strokes is certainly very various, in some much greater than in others; and as iron (the best metal for the purpose, being least apt to fuse) is cheap, it may be well enough to provide a larger canal to guide that impetuous blast than we imagine necessary; for, though one middling wire may be sufficient, two or three can do no harm. And time, with careful observations well compared, will at length point out the proper size to greater certainty.

Pointed rods erected on edifices may likewise often prevent a stroke in the following manner: An eye so situated as to view horizontally the under side of a thunder-cloud, will see it very ragged, with a number of separate fragments, or petty clouds, one under another, the lowest sometimes not far from the earth. These, as so many stepping-stones, assist in conducting a stroke between the cloud and a building. To represent these by an experiment, take two or three locks of fine, loose cotton; connect one of them with the prime conductor by a fine thread of two inches (which may be spun out of the same lock by the fingers), another to that, and the third to the second, by like threads. Turn the globe, and you will see these locks extend themselves towards the table (as the lower small clouds do towards the earth), being attracted by it; but on presenting a sharp point erect under the lowest, it will shrink up to the second, the second to the first, and all together to the prime conductor, where they will continue as long as the point continues under them. May not, in like manner, the small electrized clouds, whose equilibrium with the earth is soon restored by the point, rise up to the main body, and by that means occasion so large a vacancy as that the grand cloud cannot strike in that place?

These thoughts, my dear friend, are many of them crude and hasty; and if I were merely ambitious of acquiring some reputation in philosophy, I ought to keep them by me till corrected and improved by time and farther experience. But since even short hints and imperfect experiments in any new branch of science, being communicated, have oftentimes a good effect in exciting the attention of the ingenious to the subject, and so become the occasion of more exact disquisition and more complete discoveries, you are at liberty to communicate this paper to whom you please; it being of more importance that knowledge should increase than that your friend should be thought an accurate philosopher.

B. Franklin.

CIII

TO JAMES BOWDOIN

Philadelphia, 18 October, 1753.

Dear Sir:—

I recollect that I promised to send you Dr. Brownrigg’s Treatise on Common Salt. You will receive it herewith. I hope it may be of use in the affair of your fishery. Please to communicate it to Captain Erwin, Mr. Pitts, Mr. Boutineau, or any other of your friends who may be desirous of seeing it.

Since my return from Boston, I have been to our western frontiers on a treaty with the Ohio Indians. They complained much of the abuses they suffer from our traders, and earnestly requested us to put the trade under some regulation. If you can procure and send me your truckhouse law, and a particular account of the manner of executing it, with its consequences, &c., so that we may have the benefit of your experience, you will much oblige me; and if you have found it a useful law, I am in hopes we shall be induced to follow your good example.1

My compliments to Mrs. Bowdoin and all inquiring friends. With much respect and esteem, I am, dear Sir, &c.,

B. Franklin.

CIV

TO CADWALLADER COLDEN

Philadelphia, 25 October, 1753.

Sir:—

This last summer I have enjoyed very little of the pleasure of reading or writing. I made a long journey to the eastward, which consumed ten weeks, and two journeys to our western frontier; one of them, to meet and hold a treaty with the Ohio Indians, in company with Mr. Peters and Mr. Norris.1 I shall send you a copy of that treaty as soon as it is published. I should be glad to know whether the Act, mentioned in your History of the Five Nations, to prevent the people of New York from supplying the French with Indian goods, still subsists, and is duly executed.2

I left your book with Mr. Bowdoin, in Boston. I hope you will hear from him this winter. I observed extracts from it in all the Magazines, and in the Monthly Review, but I see no observations on it. I send you herewith Nollet’s book. M. Dalibard writes me that he is just about to publish an answer to it, which, perhaps, may save me the trouble.

I hope soon to find time to finish my new Hypothesis of Thunder and Lightning, which I shall immediately communicate to you. I sent you, by our friend Bartram, some meteorological conjectures for your amusement. When perused, please to return them, as I have no copy. With sincere esteem and respect, I am, dear Sir, &c.,

B. Franklin.

CV

TO THOMAS CLAP1

Philadelphia, 8 November, 1753.

Dear Sir:—

The first intimation I find of the new air-pump is in a piece of Mr. Watson’s read to the Royal Society, February 20th, 1752, where, describing some experiments he made in vacuo, he says: ‘The more complete the vacuum, cæteris paribus, the more considerable were the effects; and here I should not do justice to real merit were I silent in regard to Mr. Smeaton. This gentleman, with a genius truly mechanical, which enables him to give to such philosophical instruments as he executes a degree of perfection scarce to be found elsewhere; this gentleman, I say, has constructed an air-pump by which we are empowered to make Boyle’s vacuum much more perfect than heretofore. By a well conducted experiment, which admits of no doubt as to its truth, I have seen by this pump the air rarefied to one thousand times its natural state; whereas, commonly, we seldom arrive at above one hundred and fifty. As the promotion of the mechanic arts is a considerable object of our excellent institution, if this gentleman could be prevailed upon to communicate to the Royal Society that particular construction of his air-pump which enables it to execute so much more than those commonly in use, it would not fail to be an acceptable present.”

So far Mr. Watson. In April following, was read a letter from Mr. Smeaton, in which he describes his improvement, and gives a draft of his pump; the whole too long to transcribe; but it appears to me that the machine, being rather simplified than made more complex, can scarce cost more than one of the old sort, though the price is not mentioned. By only turning a cock it is at pleasure made a condensing engine; an advantage the others have not.

I have seen nothing of your searchers. Mr. Parker has received Bower, but writes me that he is at a loss how to send it, and desires you would order somebody to call for it.

I shall send the dollars for Mr. Mix per next post; for I fancy you will not now buy this apparatus here, but choose the new air-pump from England.

With my respects to all friends, I am, &c.,

B. Franklin.

CVI

TO PETER COLLINSON

Philadelphia, 23 November, 1753.

Dear Friend:—

In my last, via Virginia, I promised to send you per next ship, a small philosophical packet; but now, having got the materials (old letters and rough drafts) before me, I fear you will find it a great one. Nevertheless, as I am like to have a few days leisure before this ship sails, which I may not have again in a long time, I shall transcribe the whole and send it; for you will be under no necessity of reading it all at once, but may take it a little at a time, now and then of a winter evening. When you happen to have nothing else to do (if that ever happens), it may afford you some amusement.

B. Franklin.

Proposal of an Experiment to measure the Time taken up by an Electric Spark in moving through any given Space. By James Alexander, of New York.

read at the royal society, december 26, 1756.

If I remember right, the Royal Society made one experiment to discover the velocity of the electric fire, by a wire of about four miles in length, supported by silk, and by turning it forwards and backwards in a field, so that the beginning and end of the wire were at only the distance of two people, the one holding the Leyden bottle and the beginning of the wire, and the other holding the end of the wire and touching the ring of the bottle; but by this experiment no discovery was made, except that the velocity was extremely quick.

As water is a conductor as well as metals, it is to be considered, whether the velocity of the electric fire might not be discovered by means of water; whether a river, or lake, or sea, may not be made part of the circuit through which the electric fire passes, instead of the circuit all of wire, as in the above experiment.

Whether in a river, lake, or sea, the electric fire will not dissipate, and not return to the bottle? or will it proceed in straight lines through the water the shortest course possible back to the bottle?

If the last, then suppose one brook that falls into Delaware doth head very near to a brook that falls into Schuylkill; and let a wire be stretched and supported as before, from the head of one brook to the head of the other; and let the one end communicate with the water; and let one person stand in the other brook, holding the Leyden bottle; and let another person hold that end of the wire not in the water, and touch the ring of the bottle. If the electric fire will go as in the last question, then will it go down the one brook to Delaware or Schuylkill, and down one of them to their meeting, and up the other and the other brook; the time of its doing this may possibly be observable, and the farther upwards the brooks are chosen the more observable it would be.

Should this be not observable, then suppose the two brooks falling into Susquehanna and Delaware, and proceeding as before, the electric fire may, by that means, make a circuit round the North Cape of Virginia, and go many hundreds of miles, and in doing that, it would seem it must take some observable time.

If still no observable time is found in that experiment, then suppose the brooks falling the one into the Ohio and the other into Susquehanna or Potomac; in that the electric fire would have a circuit of some thousands of miles to go down Ohio to Mississippi, to the Bay of Mexico, round Florida, and round the South Cape of Virginia; which, I think, would give some observable time, and discover exactly the velocity.

But if the electric fire dissipates or weakens in the water, as I fear it does, these experiments will not answer.

Answer to the Foregoing

read at the royal society, december 26, 1756

Suppose a tube of any length, open at both ends, and containing a movable wire of just the same length that fills its bore. If I attempt to introduce the end of another wire into the same tube it must be done by pushing forward the wire it already contains, and the instant I press and move one end of that wire, the other end is also moved; and in introducing one inch of the same wire, I extrude, at the same time, an inch of the first from the other end of the tube.

If the tube be filled with water, and I inject an additional inch of water at one end, I force out an equal quantity at the other in the very same instant.

And the water forced out at one end of the tube is not the very same water that was forced in at the other end at the same time; it was only in motion at the same time.

The long wire, made use of in the experiment to discover the velocity of the electric fluid, is itself filled with what we call its natural quantity of that fluid, before the hook of the Leyden bottle is applied to one end of it.

The outside of the bottle being, at the time of such application, in contact with the other end of the wire, the whole quantity of electric fluid contained in the wire is, probably, put in motion at once.

For at the instant the hook connected with the inside of the bottle gives out, the coating, or outside of the bottle, draws in a portion of that fluid.

If such long wire contains precisely the quantity that the outside of the bottle demands, the whole will move out of the wire to the outside of the bottle, and the over quantity which the inside of the bottle contained, being exactly equal, will flow into the wire and remain there in the place of the quantity the wire had just parted with to the outside of the bottle.

But if the wire be so long as that one tenth (suppose) of its natural quantity is sufficient to supply what the outside of the bottle demands, in such case the outside will only receive what is contained in one tenth of the wire’s length, from the end next to it; though the whole will move so as to make room at the other end for an equal quantity issuing, at the same time, from the inside of the bottle.

So that this experiment only shows the extreme facility with which the electric fluid moves in metal; it can never determine the velocity.

And, therefore, the proposed experiment (though well imagined and very ingenious) of sending the spark round through a vast length of space, by the waters of Susquehanna, or Potomac, and Ohio, would not afford the satisfaction desired, though we could be sure that the motion of the electric fluid would be in that tract, and not under ground in the wet earth by the shortest way.

B. Franklin.

Physical and Meteorological Observations, Conjectures, and Suppositions

read at the royal society, june 3, 1756

The particles of air are kept at a distance from each other by their mutual repulsion.

Every three particles, mutually and equally repelling each other, must form an equilateral triangle.

All the particles of air gravitate towards the earth, which gravitation compresses them, and shortens the sides of the triangles; otherwise their mutual repellency would force them to greater distances from each other.

Whatever particles of other matter (not endued with that repellency) are supported in air must adhere to the particles of air, and be supported by them; for in the vacancies there is nothing they can rest on.

Air and water mutually attract each other. Hence water will dissolve in air, as salt in water.

The specific gravity of matter is not altered by dividing the matter, though the superficies be increased. Sixteen leaden bullets, of an ounce each, weigh as much in water as one of a pound, whose superficies is less.

Therefore the supporting of salt in water is not owing to its superficies being increased.

A lump of salt, though laid at rest at the bottom of a vessel of water, will dissolve therein, and its parts move every way, till equally diffused in the water; therefore there is a mutual attraction between water and salt. Every particle of water assumes as many of salt as can adhere to it; when more is added, it precipitates, and will not remain suspended.

Water, in the same manner, will dissolve in air, every particle of air assuming one or more particles of water. When too much is added, it precipitates in rain.

But there not being the same contiguity between the particles of air as of water, the solution of water in air is not carried on without a motion of the air, so as to cause a fresh accession of dry particles.

Part of a fluid, having more of what it dissolves, will communicate to other parts that have less. Thus, very salt water, coming in contact with fresh, communicates its saltness till all is equal, and the sooner, if there is a little motion of the water.

Even earth will dissolve or mix with air. A stroke of a horse’s hoof on the ground in a hot, dusty road will raise a cloud of dust that shall, if there be a light breeze, expand every way, till, perhaps, near as big as a common house. It is not by mechanical motion communicated to the particles of dust by the hoof that they fly so far, nor by the wind that they spread so wide; but the air near the ground, more heated by the hot dust struck into it, is rarefied and rises, and in rising mixes with the cooler air, and communicates of its dust to it, and it is at length so diffused as to become invisible. Quantities of dust are thus carried up in dry seasons; showers wash it from the air, and bring it down again. For, water attracting it stronger, it quits the air and adheres to the water.

Air, suffering continual changes in the degrees of its heat from various causes and circumstances, and, consequently, changes in its specific gravity, must therefore be in continual motion.

A small quantity of fire mixed with water (or degree of heat therein) so weakens the cohesion of its particles that those on the surface easily quit it, and adhere to the particles of air.

A greater degree of heat is required to break the cohesion between water and air.

Air moderately heated will support a greater quantity of water invisibly than cold air; for its particles being by heat repelled to a greater distance from each other, thereby more easily keep the particles of water that are annexed to them from running into cohesions that would obstruct, refract, or reflect the light.

Hence, when we breathe in warm air, though the same quantity of moisture may be taken up from the lungs, as when we breathe in cold air, yet that moisture is not so visible.

Water being extremely heated, that is, to the degree of boiling, its particles in quitting it so repel each other, as to take up vastly more space than before, and by that repellency support themselves, expelling the air from the space they occupy. That degree of heat being lessened, they again mutually attract; and having no air particles mixed to adhere to, by which they might be supported and kept at a distance, they instantly fall, coalesce, and become water again.

The water commonly diffused in our atmosphere never receives such a degree of heat from the sun, or other cause, as water has when boiling; it is not therefore supported by such heat, but by adhering to air.

Water being dissolved in and adhering to air, that air will not readily take up oil, because of the mutual repellency between water and oil.

Hence cold oils evaporate but slowly, the air having generally a quantity of dissolved water.

Oil being heated extremely, the air that approaches its surface will be also heated extremely; the water then quitting it, it will attract and carry off oil, which can now adhere to it. Hence the quick evaporation of oil heated to a great degree.

Oil being dissolved in air, the particles to which it adheres will not take up water.

Hence the suffocating nature of air impregnated with burnt grease, as from snuffs of candles and the like. A certain quantity of moisture should be every moment discharged and taken away from the lungs; air that has been frequently breathed is already overloaded, and for that reason can take no more, so will not answer the end. Greasy air refuses to touch it. In both cases suffocation for want of the discharge.

Air will attract and support many other substances.

A particle of air loaded with adhering water, or any other matter is heavier than before, and would descend.

The atmosphere supposed at rest, a loaded descending particle must act with a force on the particles it passes between, or meets with, sufficient to overcome, in some degree, their mutual repellency, and push them nearer to each other.

Thus, supposing the particles A, B, C, D, and the other near them, to be at the distance caused by their mutual repellency (confined by their common gravity), if A would descend to E, it must pass between B and C; when it comes between B and C, it will be nearer to them than before, and must either have pushed them nearer to F and G, contrary to their mutual repellency, or pass through by a force exceeding its repellency with them. It then approaches D, and, to move it out of the way, must act on it with a force sufficient to overcome its repellency with the two next lower particles, by which it is kept in its present situation.

Every particle of air, therefore, will bear any load inferior to the force of these repulsions.

Hence the support of fogs, mists, clouds.

Very warm air, clear, though supporting a very great quantity of moisture, will grow turbid and cloudy on the mixture of a colder air, as foggy, turbid air will grow clear by warming.

Thus the sun, shining on a morning fog, dissipates it; clouds are seen to waste in a sunshiny day.

But cold condenses and renders visible the vapor; a tankard or decanter filled with cold water will condense the moisture of warm, clear air on its outside, where it becomes visible as dew, coalesces into drops, descends in little streams.

The sun heats the air of our atmosphere most near the surface of the earth; for there, besides the direct rays, there are many reflections. Moreover the earth, itself being heated, communicates of its heat to the neighbouring air.

The higher regions, having only the direct rays of the sun passing through them, are comparatively very cold. Hence the cold air on the tops of mountains, and snow on some of them all the year, even in the torrid zone. Hence hail in summer.

If the atmosphere were all of it (both above and below) always of the same temper as to cold or heat, then the upper air would always be rarer than the lower, because the pressure on it is less; consequently lighter, and therefore would keep its place.

But the upper air may be more condensed by cold than the lower air by pressure; the lower more expanded by heat than the upper, for want of pressure. In such case the upper air will become the heavier, the lower the lighter.

The lower region of air being heated and expanded heaves up and supports for some time the colder, heavier air above, and will continue to support it while the equilibrium is kept. Thus water is supported in an inverted open glass, while the equilibrium is maintained by the equal pressure upwards of the air below; but the equilibrium by any means breaking, the water descends on the heavier side and the air rises into its place.

The lifted heavy, cold air over a heated country, becoming by any means unequally supported, or unequal in its weight, the heaviest part descends first, and the rest follows impetuously. Hence gusts after heats, and hurricanes in hot climates. Hence the air of gusts and hurricanes cold, though in hot climates and seasons; it coming from above.

The cold air descending from above, as it penetrates our warm region full of watery particles, condenses them, renders them visible, forms a cloud thick and dark, overcasting sometimes, at once large and extensive; sometimes, when seen at a distance, small at first, gradually increasing; the cold edge or surface of the cloud condensing the vapors next it, which form smaller clouds that join it, increase its bulk, it descends with the wind and its acquired weight, draws nearer the earth, grows denser with continual additions of water, and discharges heavy showers.

Small black clouds thus appearing in a clear sky, in hot climates, portend storms, and warn seamen to hand their sails.

The earth turning on its axis in about twenty-four hours, the equatorial parts must move about fifteen miles in each minute; in northern and southern latitudes this motion is gradually less to the poles, and there nothing.

If there was a general calm over the face of the globe, it must be by the air’s moving in every part as fast as the earth or sea it covers.

He that sails or rides has insensibly the same degree of motion as the ship or coach with which he is connected. If the ship strikes the shore, or the coach stops suddenly, the motion continuing in the man, he is thrown forward. If a man were to jump from the land into a swift-sailing ship, he would be thrown backward (or towards the stern), not having at first the motion of the ship.

He that travels by sea or land towards the equinoctial, gradually acquires motion; from it, loses.

But if a man were taken up from latitude 40 (where suppose the earth’s surface to move twelve miles per minute) and immediately set down at the equinoctial, without changing the motion he had, his heels would be struck up, he would fall westward. If taken up from the equinoctial and set down in latitude 40, he would fall eastward.

The air under the equator, and between the tropics, being constantly heated and rarefied by the sun, rises. Its place is supplied by air from northern and southern latitudes, which, coming from parts where the earth and air had less motion, and not suddenly acquiring the quicker motion of the equatorial earth,1 appears an east wind blowing westward, the earth moving from west to east, and slipping under the air.

Thus when we ride in a calm it seems a wind against us; if we ride with the wind, and faster, even that will seem a small wind against us.

The air rarefied between the tropics, and rising, must flow in the higher region north and south. Before it rose, it had acquired the greatest motion the earth’s rotation could give it. It retains some degree of this motion, and descending in higher latitudes, where the earth’s motion is less, will appear a westerly wind, yet tending towards the equatorial parts, to supply the vacancy occasioned by the air of the lower regions flowing thitherwards.

Hence our general cold winds are about northwest; our summer cold gusts the same.

The air in sultry weather, though not cloudy, has a kind of haziness in it, which makes objects at a distance appear dull and indistinct. This haziness is occasioned by the great quantity of moisture equally diffused in that air. When, by the cold wind blowing down among it, it is condensed into clouds, and falls in rain, the air becomes purer and clearer. Hence, after gusts, distant objects appear distinct, their figures sharply terminated.

Extreme cold winds congeal the surface of the earth, by carrying off its fire. Warm winds, afterwards blowing over that frozen surface, will be chilled by it. Could that frozen surface be turned under, and a warmer turned up from beneath it, those warm winds would not be chilled so much.

The surface of the earth is also sometimes much heated by the sun; and such heated surface, not being changed, heats the air that moves over it.

Seas, lakes, and great bodies of water, agitated by the winds, continually change surfaces; the cold surface in winter is turned under by the rolling of the waves, and a warmer turned up; in summer, the warm is turned under, and colder turned up. Hence the more equal temper of sea water, and the air over it. Hence, in winter, winds from the sea seem warm, winds from the land cold. In summer, the contrary.

Therefore the lakes northwest of us,1 as they are not so much frozen nor so apt to freeze as the earth, rather moderate than increase the coldness of our winter winds.

The air over the sea being warmer, and therefore lighter in winter than the air over the frozen land, may be another cause of our general northwest winds, which blow off to sea at right angles from our North American coast; the warm, light sea air rising, the heavy, cold land air pressing into its place.

Heavy fluids descending frequently form eddies or whirlpools, as is seen in a funnel where the water acquires a circular motion, receding every way from a centre, and leaving a vacancy in the middle, greatest above, and lessening downwards, like a speaking-trumpet, its big end upwards.

Air descending or ascending may form the same kind of eddies or whirlings, the parts of air acquiring a circular motion, and receding from the middle of the circle by a centrifugal force, and leaving there a vacancy, if descending, greatest above, and lessening downwards; if ascending, greatest below, and lessening upwards, like a speaking-trumpet, standing its big end on the ground.

When the air descends with violence in some places, it may rise with equal violence in others, and form both kinds of whirlwinds.

The air, in its whirling motion receding every way from the centre or axis of the trumpet, leaves there a vacuum, which cannot be filled through the sides, the whirling air, as an arch, preventing; it must then press in at the open ends.

The greatest pressure inwards must be at the lower end, the greatest weight of the surrounding atmosphere being there. The air entering rises within, and carries up dust, leaves, and even heavier bodies that happen in its way as the eddy or whirl passes over land.

If it passes over water, the weight of the surrounding atmosphere forces up the water into the vacuity, part of which, by degrees, joins with the whirling air, and adding weight, and receiving accelerated motion, recedes still farther from the centre or axis of the trump as the pressure lessens, and at last, as the trump widens, is broken into small particles, and so united with air as to be supported by it, and become black clouds at the top of the trump.

Thus these eddies may be whirlwinds at land, water-spouts at sea. A body of water so raised may be suddenly let fall when the motion, &c., has not strength to support it, or the whirling arch is broken so as to admit the air; falling in the sea it is harmless, unless ships happen under it; but if in the progressive motion of the whirl it has moved from the sea over the land, and then breaks, sudden, violent, and mischievous torrents are the consequences.

B. Franklin.

end of vol. ii

[1 ]Probably the ground is never so dry.—F.

[1 ]We afterwards found that it failed after one stroke with a large bottle, and the continuity of the gold appearing broken, and many of its parts dissipated, the electricity could not pass the remaining parts without leaping from part to part through the air, which always resists the motion of this fluid, and was probably the cause of the gold’s not conducting so well as before; the number of interruptions in the line of gold, making, when added together, a space larger, perhaps, than the striking distance.—F.

[1 ]The river that washes one side of Philadelphia, as the Delaware does the other; both are ornamented with the summer habitations of the citizens and the agreeable mansions of the principal people of this colony.—F.

[2 ]As the possibility of this experiment has not been easily conceived, I shall here describe it. Two iron rods, about three feet long, were planted just within the margin of the river, on the opposite sides. A thick piece of wire, with a small round knob at its end, was fixed on the top of one of the rods, bending downwards, so as to deliver commodiously the spark upon the surface of the spirit. A small wire fastened by one end to the handle of the spoon, containing the spirit, was carried across the river and supported in the air by the rope commonly used to hold by in drawing the ferry-boats over. The other end of this wire was tied round the coating of the bottle; which being charged, the spark was delivered from the hook to the top of the rod standing in the water on that side. At the same instant the rod on the other side delivered a spark into the spoon and fired the spirit, the electric fire returning to the coating of the bottle, through the handle of the spoon and the supported wire connected with them.

That the electric fire thus actually passes through the water, has since been satisfactorily demonstrated to many by an experiment of Mr. Kinnersley’s, performed in a trough of water about ten feet long. The hand, being placed under water in the direction of the spark (which always takes the straight or shortest course, if sufficient, and other circumstances are equal), is struck and penetrated by it as it passes.—F.

[1 ]An electrified bumper is a small, thin, glass tumbler, nearly filled with wine, and electrified as the bottle. This when brought to the lips gives a shock, if the party be close shaved, and does not breathe on the liquor.—April 29, 1749.—F.

[1 ]This was tried with a bottle containing about a quart. It is since thought that one of the large glass jars mentioned in these papers might have killed him, though wet.—F.

[1 ]We have since fired spirits without heating them, when the weather is warm. A little, poured into the palm of the hand, will be warmed sufficiently by the hand, if the spirit be well rectified. Ether takes fire most readily.—F.

[1 ]These facts, though related in several accounts, are now doubted: since it has been observed that the parts of a bell-wire which fell on the floor, being broken and partly melted by lightning, did actually burn into the boards. (See Philosophical Transactions, vol. li., Part I.) And Mr. Kinnersley has found that a fine iron wire, melted by electricity, has had the same effect.—F.

[1 ]Franklin’s wife was a Miss Read.

[1 ]His son, William, had been an officer in the Pennsylvania forces raised for an expedition against Canada, in the year 1746.

[1 ]In a letter from James Logan to Mr. Collinson, dated February 14, 1750, he says: “Our Benjamin Franklin is certainly an extraordinary man, one of a singular good judgment, but of equal modesty. He is clerk of our Assembly, and there, for want of other employment, while he sat idle, he took it into his head to think of magical squares, in which he outdid Frenicle himself, who published above eighty pages in folio on that subject alone.”

[1 ]In the plate they are distinguished by dashed or dotted lines, as different as the engraver could well make them.—F.

[1 ]Professor Bache, of the University of Pennsylvania, has shown that the eclipse of the moon here alluded to happened in the evening of the 21st of October, 1743; as may be seen in his tract entitled. “An Attempt to Fix the Date of Observation of Dr. Franklin, in Relation to the Northeast Storms of the Atlantic Coast of the United States,” published in the Journal of the Franklin Institute, in the year 1833. It appears that Dr. Franklin was the first discoverer of the above facts respecting northeast storms.—Sparks.

[1 ]A Swedish botanist, sent by the Swedish government, at the suggestion of Linnæus, to make a botanical tour of North America. He arrived in 1748 and returned in 1751, having travelled and collected specimens in New York, Pennsylvania, and Canada. He published an account of his travels in Swedish in 1753-1761 in three vols. It was translated into English, Dutch, and German.—Editor.

[2 ]Lewis Evans, author of Geographical, Historical, Political, Philosophical, and Mechanical Essays, of some other tracts, and of a map of the Middle Colonies.

[1 ]The cushion being afterwards covered with a long flap of buckskin, which might cling to the globe, and care being taken to keep that flap of a due temperature between too dry and too moist, we found so much more of the electric fluid was obtained as that one hundred and fifty turns were sufficient. 1753.—F.

[1 ]See the ingenious essays on Electricity, in the Transactions, by Mr. Ellicot.—F.

[1 ]See Supra, p. 182.

[1 ]See the first sixteen sections of the former paper, No. LXI.

[1 ]See § 10 of paper No. LXI.

[1 ]In the dark the electric fluid may be seen on the cushion in two semi-circles or half-moons, one on the fore part, the other on the back part of the cushion, just where the globe and cushion separate. In the fore crescent the fire is passing out of the cushion into the glass, in the other it is leaving the glass and returning into the back part of the cushion. When the prime conductor is applied to take it off the glass, the back crescent disappears.—F.

[2 ]Gilt paper, with the gilt face next the glass, does well.

[1 ]See paper No. LXI., § 15.

[1 ]Dr. Samuel Johnson was the first president of King’s (now Columbia) College, New York. This letter appears to have been written at the time of the first establishment of the College of Philadelphia, the presidency of which institution had been offered to him, but was declined.

[1 ]Mr. Bowdoin was at this time twenty-three years old. He became distinguished afterwards as a philosopher and statesman, being one of the principal founders and the first president of the American Academy of Arts and Sciences. He took an active and prominent part in the events of the American Revolution, and was subsequently governor of Massachusetts.—Sparks.

[1 ]A copy of this letter was found among Governor Bowdoin’s papers, without the name of the person to whom it was addressed.—Sparks.

[1 ]This proposition is since found to be too general, Mr. Wilson having discovered that melted wax and rosin will also conduct.

[1 ]The experiment here mentioned was thus made. An empty phial was stopped with a cork. Through the cork passed a thick wire, as usual in the Leyden experiment, which wire almost reached the bottom. Through another part of the cork passed one leg of a small glass siphon; the other leg on the outside came down almost to the bottom of the phial. This phial was held a short time in the hand, which, warming and of course rarefying the air within, drove a small part of it out through the siphon. Then a little red ink in a tea-spoon was applied to the opening of the outer leg of the siphon; so that as the air within cooled, a little of the ink might rise in that leg. When the air within the bottle came to be of the same temperature of that without, the drop of red ink would rest in a certain part of the leg. But the warmth of a finger applied to the phial would cause that drop to descend, as the least outward coolness applied would make it ascend. When it had found its situation, and was at rest, the wire was electrified by a communication from the prime conductor. This was supposed to give an electric atmosphere to the wire within the bottle, which might likewise rarefy the included air, and of course depress the drop of ink in the siphon. But no such effect followed.—F.

[1 ]The prospect of a rupture between the English and French governments in 1750-51 were so threatening that the friendship of the Indian tribes became a matter of supreme importance, and how to secure it occupied the attention of leading men throughout the colonies. In the appendix to the second edition of a pamphlet entitled The Importance of Gaining and Preserving the Friendship of the Indians to British Interests Considered, London, 1782, is a letter which bears so many distinctive traces of Franklin’s authorship that it has seemed to merit a place in this collection.

The editor is happy to acknowledge his obligations to Professor Edward Eggleston for calling his attention to this letter, which that gentleman found in the Harvard College Library. “I think,” says Professor Eggleston, in a note to the editor, “the pamphlet is anonymous, but I have a minute that the author is Archibald Kennedy. The first edition, N. Y., 1751, and the letter I believe to be Franklin’s was dated at Philadelphia and addressed to the printer of the first edition.—Parker.”

[1 ]Nor will tables which are accurately calculated at one period, necessarily continue to be correct in the same country at another period. The chances of life have been ascertained to be greater in Europe during the last half century than they were formerly.—W. Phillips.

[1 ]It is a curious fact that to this tract the world is largely, if not entirely, indebted for a book which, in its day, produced a remarkable sensation, and the theories of which are still occasionally debated. Malthus’ Essay on Population would probably never have been written but for the support of his theory which he was able to extract from the 22d clause of this paper. In that clause Franklin, with his habitual caution, referring to the number of “English souls” then in North America, says: “This million doubling, suppose but once in twenty-five years, will in another century be more than the people of England.” Malthus accepts this rather hypothetical statement as evidence of a demonstrated fact, and proceeds to build upon it his chimerical theory that the population of the earth increases in a geometrical ratio, while the means for its subsistence increases only in an arithmetical ratio William Godwin wrote a reply to Malthus entitled An Enquiry concerning the Power of Increase in the Numbers of Mankind, being an Answer to Mr. Malthus’ Essay on that Subject, which was published in 1820. He did not see any way of demolishing Malthus but by first trying to demolish the statement of Franklin. “Dr. Franklin,” he says, “is in this case particularly the object of our attention, because he was the first man who started the idea of the people of America being multiplied by procreation so as to double every twenty-five years. Dr. Franklin, born in Boston, was eminently an American patriot; and the paper from which these extracts are taken, was expressly written to exalt the importance and glory of his country.” Mr. Godwin, who is open to the suspicion of having taken his knowledge of Franklin’s paper at second-hand, and to have never read more of it than was quoted by Malthus, stumbles into a curious blunder as to its date. He says (p. 119) “it was written in 1731 when the author was twenty-five years of age,” meaning evidently to imply thereby that it was the work of an immature political economist. The fact was that Franklin’s paper was written in 1751, when he was forty-five years of age. Franklin understood what he was writing about much better than Godwin, and time and science have fully justified all the statements which Godwin contested.

[1 ]The explanation here referred to will be found in the following paragraph of a letter written to Franklin by Bowdoin on 21 Dec., 1751. Franklin had in September of the same year given Mr. Kinnersley a letter of introduction to Bowdoin, to pave the way for a course of lectures in Boston on electricity, which Mr. Kinnersley had prepared and delivered in Philadelphia:

“The electrical fire passing through the air has the same crooked direction as lightning. This appearance I endeavour to account for thus. Air is an electric per se; therefore there must be a mutual repulsion between air and the electrical fire. A column or cylinder of air having the diameter of its base equal to the diameter of the electrical spark, intervenes between that part of the body which the spark is drawn from and that of the body it aims at. The spark acts upon this column, and is acted upon by it more strongly than any other neighbouring portion of air. The column being thus acted upon, becomes more dense, and, being more dense, repels the spark more strongly; its repellency being in proportion to its density. Having acquired by being condensed a degree of repellency greater than its natural, it turns the spark out of its straight course, the neighbouring air, which must be less dense, and therefore has a smaller degree of repellency, giving it a more ready passage. The spark having taken a new direction must now act on, or most strongly repel, the column of air which lies in that direction, and consequently must condense that column in the same manner as the former, when the spark must again change its course, which course will be repeatedly changed, till the spark reaches the body that attracted it.”—Ed.

[1 ]The Rev. Ebenezer Kinnersley was a professor in the College of Philadelphia.—Editor.

[2 ]The experiments here referred to were described in the following letter from Mr. Kinnersley to Dr. Franklin:

[Boston] 3 February, 1752.

Sir:—

I have the following experiments to communicate. I held in one hand a wire, which was fastened at the other end to the handle of a pump, in order to try whether the stroke from the prime conductor, through my arms, would be any greater than when conveyed only to the surface of the earth, but could discover no difference.

I placed the needle of a compass on the point of a long pin, and, holding it in the atmosphere of the prime conductor, at the distance of about three inches, found it to whirl round like the flyers of a jack, with great rapidity.

I suspended with silk a cork ball, about the bigness of a pea and presented to it rubbed amber, sealing-wax, and sulphur, by each of which it was strongly repelled; then I tried rubbed glass and China, and found that each of these would attract it, until it became electrified again, and then it would be repelled as at first; and while thus repelled by the rubbed glass or China, either of the others when rubbed would attract it. Then I electrified the ball with the wire of a charged phial, and presented to it rubbed glass (the stopper of a decanter) and a China tea-cup, by which it was as strongly repelled as by the wire but when I presented either of the other rubbed electrics, it would be strongly attracted, and when I electrified it by either of these, till it became repelled, it would be attracted by the wire of the phial, but be repelled by its coating.

These experiments surprised me very much, and have induced me to infer the following paradoxes.

1. If a glass globe be placed at one end of a prime conductor, and a sulphur one at the other end, both being equally in good order, and in equal motion, not a spark of fire can be obtained from the conductor; but one globe will draw out as fast as the other gives in.

2. If a phial be suspended on the conductor, with a chain from its coating to the table, and only one of the globes be made use of at a time, twenty turns of the wheel, for instance, will charge it, after which, so many turns of the other wheel will discharge it, and as many more will charge it again.

3. The globes being both in motion, each having a separate conductor, with a phial suspended on one of them, and the chain of it fastened to the other, the phial will become charged; one globe charging positively, the other negatively.

4. The phial being thus charged, hang it in like manner on the other conductor, set both wheels a going again, and the same number of turns that charged it before will now discharge it, and the same number repeated will charge it again.

5. When each globe communicates with the same prime conductor, having a chain hanging from it to the table, one of them, when in motion (but which I cannot say), will draw fire up through the cushion, and discharge it through the chain; the other will draw it up through the chain, and discharge it through the cushion.

[1 ]The discoveries of the late ingenious Mr. Symmer, on the positive and negative electricity produced by the mutual friction of white and black silk, etc., afford hints for farther improvements to be made with this view.—F.

[1 ]Dr. Perkins, of Boston, had asked Franklin for the number that had died of inoculation in Philadelphia, at the instance of Dr. Douglass, who designed to write something on the small-pox.

[1 ]See this paper Supra, p. 338.

[1 ]This is the only evidence in our literature, so far as I know, that any of this sect, for whose principles Fenelon suffered and Molinos died, ever found a refuge in the United States.—Ed.

[1 ]The bookseller in London, who first published Franklin’s papers on electricity.

[1 ]The paper alluded to, of which fifty copies were struck off for distribution, was entitled, Letters relating to a Transit of Mercury over the Sun, which is to happen May 6, 1753.

[1 ]As early as 1743, Franklin had endeavored to procure the establishment of an Academy in Philadelphia. His efforts were not successful till 1749, when, chiefly through his instrumentality, the Academy was instituted and went into operation. Franklin was chosen the first president of the Board of Trustees. From this institution arose, first the College of Philadelphia, and afterwards the present University of Pennsylvania. The Reverend William Smith was appointed Provost of the Academy in 1754, and he filled that office, at the head of the Academy and College successively, for the period of thirty-seven years, till the University was founded in 1791. A full account of these institutions, in their various stages, may be seen in Wood’s History of the University of Pennsylvania, contained in the third volume of the Memoirs of the Historical Society of Pennsylvania.

[2 ]A General Idea of the College of Mirania.—Stuber.

[1 ]The Rev. Francis Alison, afterwards Vice-Provost of the College in Philadelphia.—Stuber.

[2 ]Theophilus Grew, afterwards Professor of Mathematics in the College.—Stuber.

[3 ]Those assistants were at that time Charles Thomson, afterwards Secretary of Congress, Paul Jackson, and Jacob Duché.—Stuber.

[1 ]The name given to the principal or head of the ideal college, the system of education in which has nevertheless been nearly realized, or followed as a model, in the College and Academy of Philadelphia and some other American seminaries for many years past.—Stuber.

[1 ]The quotation alluded to (from the London Monthly Review for 1749) was judged to reflect too severely on the discipline and government of the English Universities of Oxford and Cambridge, and was expunged from the following editions of this work.—Stuber.

[1 ]This letter was first printed in the Gentleman’s Magazine for January, 1834, as contained in the Diary of Mr. Thomas Green. The person who communicated it to the Magazine says the original manuscript, from which he transcribed the letter, ends thus abruptly, and that the remainder could not be recovered. He conjectures that the words of Milton, alluded to by the writer are the following:

“Yet sometimes nations will decline so low
From virtue, which is reason, that no wrong
But justice, and some fatal curse annex’d,
Deprives them of their outward liberty,
Their inward lust.’
Paradise Lost, xii., 97.

[1 ]Mr. Bowdoin replied as follows, in a letter dated at Boston, November 12th:—“Our Indians formerly (as yours now) made great complaints of the abuses they suffered from private traders, which induced the government to erect truckhouses for them; where they have since been supplied with the goods they wanted in a much better manner both in regard of the quality and price of them, and with more certainty than the private traders could. The government used to put an advance on the goods supplied, but now they let the Indians have them in the small quantities they want at the same rate they are purchased here in the wholesale way, and allow them for their peltry what it sells for here; and, notwithstanding, they are frequently complaining about the prices of the exchanged commodities, and say that the French supply them at a cheaper rate, and allow them more for their skins than we do; but some allowance is to be made for this account of theirs.

“The best method we can go into, is to supply them with what they want at the cheapest rate possible, which will not only undermine the French trade with them, but in proportion thereto bring them into our interest and friendship against the French; for trade and commerce between nation and nation, especially when carried on to mutual advantage, have a natural tendency to beget and confirm a mutual and lasting friendship. Another good effect of this method is, that it prevents the Indians from being concerned with private traders; for not being able to supply them at so low a rate as the government, the Indians will not trade with them, and it is therefore a more effectual bar against private trade than all the laws that can be invented.

Our truckhouses are built in form of a square, each side one hundred and fifty feet or more, at each corner a flanker, in which is a couple of cannon; three sides of the square are built upon to accommodate the garrison and for storehouses, the whole being surrounded with palisades.”

[1 ]This treaty, or rather conference, was held at Carlisle, in Pennsylvania, with deputies from several tribes of western Indians. See Sparks’s Life of Washington, 2d edition, p. 25.

[2 ]To this inquiry Mr. Colden replied, November 19th:—“We have at present no law in this province for restraining the trade to Canada, except that by which a duty is laid on Indian goods sold out of the city of Albany and applied for support of the garrison at Oswego. It is certain that a very considerable trade is carried on between Albany and Canada by means of the Caghnawaga or French Indians, all of them deserters from the Five Nations. When I was last at Albany, there were at least two hundred of them, stout young fellows, at one time in the town. The Indians have passports from the governor of Canada, and I therefore conclude that this trade is thought beneficial to the French interest, and it may be a great inducement to our Indians to desert, by the benefit they receive from it; for none are allowed to be the carriers between Albany and Canada but French Indians.”

[1 ]President of Yale College.

[1 ]See a paper on this subject, by the late ingenious Mr. Hadley, in the Philosophical Transactions, wherein this hypothesis for explaining the trade-winds first appeared.—F.

[1 ]In Pennsylvania.

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XCIV

TO CADWALLADER COLDEN

Dear Sir:—

XCV

TO JOHN PERKINS

Sir:—

XCVI

TO JAMES BOWDOIN

Dear Sir:—

Your most humble servant,

XCVII

TO JARED ELIOT

Dear Sir:—

XCVIII

TO JAMES BOWDOIN

Sir:—

Your most humble servant,

XCIX

TO WILLIAM SMITH1

Sir:—

C

TO WILLIAM SMITH

Sir:—

CI

TO PETER COLLINSON

Sir:—

CII

TO PETER COLLINSON

Sir:—

CIII

TO JAMES BOWDOIN

Dear Sir:—

CIV

TO CADWALLADER COLDEN

Sir:—

CV

TO THOMAS CLAP1

Dear Sir:—

CVI

TO PETER COLLINSON

Dear Friend:—

Answer to the Foregoing

Physical and Meteorological Observations, Conjectures, and Suppositions

Sir:—