Front Page Titles (by Subject) 1752: LXXXIV: TO JAMES BOWDOIN - The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753
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1752: LXXXIV: TO JAMES BOWDOIN - Benjamin Franklin, The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753 
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).
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TO JAMES BOWDOIN
read at the royal society, may 27, 1756
Philadelphia, 24 January, 1752.
I am glad to learn by your favor of the 21st past, that Mr. Kinnersley’s lectures have been acceptable to the gentlemen of Boston, and are like to prove serviceable to himself.
I thank you for the countenance and encouragement you have so kindly afforded my fellow-citizen.
I send you enclosed an extract of a letter containing the substance of what I observed concerning the communication of magnetism to needles by electricity. The minutes I took at the time of the experiments are mislaid. I am very little acquainted with the nature of magnetism. Dr. Gawin Knight, inventor of the steel magnets, has wrote largely on that subject; but I have not yet had leisure to peruse his writings with the attention necessary to become master of his doctrine.
Your explication of the crooked direction of lightning1 appears to me both ingenious and solid. When we can account as satisfactorily for the electrification of clouds, I think that branch of natural philosophy will be nearly complete.
The air undoubtedly obstructs the motion of the electric fluid. Dry air prevents the dissipation of an electric atmosphere, the denser the more, as in cold weather. I question whether such an atmosphere can be retained by a body in vacuo. A common electrical phial requires a non-electric communication from the wire to every part of the charged glass; otherwise, being dry and clean, and filled with air only, it charges slowly and discharges gradually by sparks, without a shock; but, exhausted of air, the communication is so open and free between the inserted wire and surface of the glass, that it charges as readily, and shocks as smartly, as if filled with water; and I doubt not but that in the experiment you propose the sparks would not only be near straight in vacuo, but strike at a greater distance than in the open air, though perhaps there would not be a loud explosion. As soon as I have a little leisure, I will make the experiment and send you the result.
My supposition, that the sea might possibly be the grand source of lightning, arose from the common observation of its luminous appearance in the night, on the least motion; an appearance never observed in fresh water. Then I knew that the electric fluid may be pumped up out of the earth by the friction of a glass globe on a non-electric cushion; and that notwithstanding the surprising activity and swiftness of that fluid and the non-electric communication between all parts of the cushion and the earth, yet quantities would be snatched up by the revolving surface of the globe, thrown on the prime conductor, and dissipated in air. How this was done, and why that subtile, active spirit did not immediately return again from the globe into some part or other of the cushion, and so into the earth was difficult to conceive; but whether from its being opposed by a current setting upwards to the cushion, or from whatever other cause, that it did not so return was an evident fact. Then I considered the separate particles of water as so many hard spherules, capable of touching the salt only in points, and imagined a particle of salt could therefore no more be wet by a particle of water, than a globe by a cushion; that there might therefore be such a friction between these originally constituent particles of salt and water, as in a sea of globes and cushions; that each particle of water on the surface might obtain, from the common mass, some particles of the universally diffused, much finer, and more subtile electric fluid, and, forming to itself an atmosphere of those particles, be repelled from the then generally electrified surface of the sea, and fly away with them into the air. I thought, too, that possibly the great mixture of particles electric per se in the ocean water might, in some degree, impede the swift motion and dissipation of the electric fluid through it to the shores, &c. But having since found, that salt in the water of an electric phial does not lessen the shock; and having endeavoured in vain to produce that luminous appearance from a mixture of salt and water agitated; and observed, that even the sea-water will not produce it after some hours’ standing in a bottle; I suspect it to proceed from some principle yet unknown to us (which I would gladly make some experiments to discover, if I lived near the sea), and I grow more doubtful of my former supposition, and more ready to allow weight to that objection (drawn from the activity of the electric fluid, and the readiness of water to conduct), which you have indeed stated with great strength and clearness.
In the mean time, before we part with this hypothesis, let us think what to substitute in its place. I have sometimes queried, whether the friction of the air, an electric per se, in violent winds, among trees, and against the surface of the earth, might not pump up, as so many glass globes, quantities of the electric fluid, which the rising vapors might receive from the air, and retain in the clouds they form; on which I should be glad to have your sentiments. An ingenious friend of mine supposes the land clouds more likely to be electrified than the sea clouds. I send his letter for your perusal, which please to return to me.
I have wrote nothing lately on electricity, nor observed any thing new that is material, my time being much taken up with other affairs. Yesterday I discharged four jars through a fine wire, tied up between two strips of glass; the wire was in part melted, and the rest broke into small pieces, from half an inch long to half a quarter of an inch. My globe raises the electric fire with greater ease, in much greater quantities, by the means of a wire extended from the cushion to the iron pin of a pump-handle behind my house, which communicates by the pump-spear with the water in the well.
By this post I send to Dr. Perkins, who is curious in that way, some meteorological observations and conjectures, and desire him to communicate them to you, as they may afford you some amusement, and I know you will look over them with a candid eye. By throwing our occasional thoughts on paper, we more readily discover the defects of our opinions, or we digest them better, and find new arguments to support them. This I sometimes practise; but such pieces are fit only to be seen by friends.
I am, with great respect, &c.,
TO E. KINNERSLEY, AT BOSTON1
Philadelphia, 2 March, 1752.
I thank you for the experiments communicated.2 I sent immediately for your brimstone globe, in order to make the trials you desired, but found it wanted centres, which I have not time now to supply; but, the first leisure, I will get it fitted for use, try the experiments, and acquaint you with the result.
In the mean time I suspect that the different attractions and repulsions you observed, proceeded rather from the greater or smaller quantities of the fire you obtained from different bodies, than from its being of a different kind, or having a different direction. In haste, I am, &c.,
TO E. KINNERSLEY, AT BOSTON
Philadelphia, 16 March, 1752.
Having brought your brimstone globe to work, I tried one of the experiments you proposed, and was agreeably surprised to find that the glass globe being at one end of the conductor, and the sulphur globe at the other end, both globes in motion, no spark could be obtained from the conductor, unless when one globe turned slower, or was not in so good order as the other; and then the spark was only in proportion to the difference, so that turning equally, or turning that slowest which worked best, would again bring the conductor to afford no spark.
I found also that the wire of a phial charged by the glass globe, attracted a cork ball that had touched the wire of a phial charged by the brimstone globe, and vice versâ, so that the cork continued to play between the two phials, just as when one phial was charged through the wire, the other through the coating, by the glass globe alone. And two phials charged, the one by the brimstone globe, the other by the glass globe, would be both discharged by bringing their wires together, and shock the person holding the phials.
From these experiments one may be certain that your second, third, and fourth proposed experiments would succeed exactly as you suppose, though I have not tried them, wanting time. I imagine it is the glass globe that charges positively, and the sulphur negatively, for these reasons. 1. Though the sulphur globe seems to work equally well with the glass one, yet it can never occasion so large and distant a spark between my knuckle and the conductor, when the sulphur one is working, as when the glass one is used; which, I suppose, is occasioned by this, that bodies of a certain bigness cannot so easily part with a quantity of electrical fluid they have and hold attracted within their substance, as they can receive an additional quantity upon their surface by way of atmosphere. Therefore so much cannot be drawn out of the conductor, as can be thrown on it. 2. I observe that the stream or brush of fire appearing at the end of a wire connected with the conductor, is long, large, and much diverging, when the glass globe is used, and makes a snapping (or rattling) noise; but when the sulphur one is used, it is short, small, and makes a hissing noise; and just the reverse of both happens, when you hold the same wire in your hand, and the globes are worked alternately: the brush is large, long, diverging, and snapping (or rattling), when the sulphur globe is turned; short, small, and hissing, when the glass globe is turned. When the brush is long, large, and much diverging, the body to which it joins seems to me to be throwing the fire out; and when the contrary appears, it seems to be drinking in. 3. I observe that when I hold my knuckle before the sulphur globe, while turning, the stream of fire between my knuckle and the globe seems to spread on its surface, as if it flowed from the finger; on the glass globe it is otherwise. The cool wind (or what was called so), that we used to feel as coming from an electrified point, is, I think, more sensible when the glass globe is used, than when the sulphur one. But these are hasty thoughts. As to your fifth paradox, it must likewise be true, if the globes are alternately worked; but, if worked together, the fire will neither come up nor go down by the chain, because one globe will drink it as fast as the other produces it.
I should be glad to know whether the effects would be contrary, if the glass globe is solid, and the sulphur globe is hollow; but I have no means at present of trying.
In your journeys, your glass globes meet with accidents, and sulphur ones are heavy and inconvenient. Query. Would not a thin plane of brimstone, cast on a board, serve on occasion as a cushion, while a globe of leather stuffed (properly mounted) might receive the fire from the sulphur, and charge the conductor positively? Such a globe would be in no danger of breaking.1 I think I can conceive how it may be done; but have not time to add more than that I am,
TO CADWALLADER COLDEN
read at the royal society, november 11, 1756
Philadelphia, 23 April, 1752.
In considering your favor of the 16th past, I recollected my having wrote you answers to some queries concerning the difference between electrics per se and non-electrics, and the effects of air in electrical experiments, which, I apprehend, you may not have received. The date I have forgotten.
We have been used to call those bodies electrics per se, which would not conduct the electric fluid. We once imagined that only such bodies contained that fluid; afterwards that they had none of it, and only educed it from other bodies; but further experiments showed our mistake. It is to be found in all matter we know of; and the distinction of electrics per se and non-electrics should now be dropped as improper, and that of conductors and non-conductors assumed in its place, as I mentioned in those answers.
I do not remember any experiment by which it appeared that high-rectified spirit will not conduct; perhaps you have made such. This I know, that wax, rosin, brimstone, and even glass, commonly reputed electrics per se, will, when in a fluid state, conduct pretty well. Glass will do it when only red-hot. So that my former position, that only metals and water were conductors, and other bodies more or less such as they partook of metal or moisture, was too general.
Your conception of the electric fluid, that it is incomparably more subtile than air, is undoubtedly just. It pervades dense matter with the greatest ease; but it does not seem to mix or incorporate willingly with mere air, as it does with other matter. It will not quit common matter to join with air. Air obstructs, in some degree, its motion. An electric atmosphere cannot be communicated at so great a distance, by far, through intervening air as through a vacuum. Who knows, then, but there may be, as the ancients thought, a region of this fire above our atmosphere, prevented by our air and its own too great distance for attraction, from joining our earth? Perhaps where the atmosphere is rarest this fluid may be densest, and nearer the earth, where the atmosphere grows denser, this fluid may be rarer, yet some of it be low enough to attach itself to our highest clouds, and thence they, becoming electrified may be attracted by and descend towards the earth and discharge their watery contents, together with that ethereal fire. Perhaps the auroræ boreales are currents of this fluid in its own region, above our atmosphere, becoming from their motion, visible. There is no end to conjectures. As yet we are but novices in this branch of natural knowledge.
You mention several differences of salts in electrical experiments. Were they all equally dry? Salt is apt to acquire moisture from a moist air, and some sorts more than others. When perfectly dried by lying before a fire, or on a stove, none that I have tried will conduct any better than so much glass.
New flannel, if dry and warm, will draw the electric fluid from non-electrics, as well as that which has been worn.
I wish you had the convenience of trying the experiments you seem to have such expectations from, upon various kinds of spirits, salts, earth, &c. Frequently, in a variety of experiments, though we miss what we expected to find, yet something valuable turns out, something surprising and instructing, though unthought of.
I thank you for communicating the illustration of the theorem concerning light. It is very curious. But I must own I am much in the dark about light. I am not satisfied with the doctrine that supposes particles of matter, called light, continually driven off from the sun’s surface, with a swiftness so prodigious! Must not the smallest particle conceivable have, with such a motion, a force exceeding that of a twenty-four pounder discharged from a cannon? Must not the sun diminish exceedingly by such a waste of matter; and the planets, instead of drawing nearer to him, as some have feared, recede to greater distances through the lessened attraction? Yet these particles, with this amazing motion, will not drive before them, or remove the least and lightest dust they meet with. And the sun, for aught we know, continues of his ancient dimensions, and his attendants move in their ancient orbits.
May not all the phenomena of light be more conveniently solved, by supposing universal space filled with a subtile elastic fluid, which, when at rest, is not visible, but whose vibrations affect that fine sense in the eye, as those of air do the grosser organs of the ear? We do not, in the case of sound, imagine that any sonorous particles are thrown off from a bell, for instance, and fly in straight lines to the ear; why must we believe that luminous particles leave the sun and proceed to the eye? Some diamonds, if rubbed, shine in the dark, without losing any part of their matter. I can make an electrical spark as big as the flame of a candle, much brighter, and therefore, visible farther; yet this is without fuel; and I am persuaded no part of the electric fluid flies off in such case to distant places, but all goes directly, and is to be found in the place to which I destine it. May not different degrees of the vibration of the above-mentioned universal medium occasion the appearances of different colors? I think the electric fluid is always the same; yet I find that weaker and stronger sparks differ in apparent color; some white, blue, purple, red; the strongest, white; weak ones, red. Thus different degrees of vibration given to the air produce the seven different sounds in music, analogous to the seven colors, yet the medium, air, is the same.
If the sun is not wasted by expense of light, I can easily conceive that he shall otherwise always retain the same quantity of matter; though we should suppose him made of sulphur constantly flaming. The action of fire only separates the particles of matter; it does not annihilate them. Water, by heat raised in vapor, returns to the earth in rain; and if we could collect all the particles of burning matter that go off in smoke, perhaps they might, with the ashes, weigh as much as the body before it was fired; and if we could put them into the same position with regard to each other, the mass would be the same as before, and might be burnt over again. The chemists have analyzed sulphur, and find it composed, in certain proportions, of oil, salt, and earth; and having by the analysis discovered those proportions, they can, of those ingredients, make sulphur. So we have only to suppose, that the parts of the sun’s sulphur, separated by fire, rise into his atmosphere, and there, being freed from the immediate action of the fire, they collect into cloudy masses, and growing by degrees too heavy to be longer supported, they descend to the sun and are burnt over again. Hence the spots appearing on his face, which are observed to diminish daily in size, their consuming edges being of particular brightness.
It is well we are not, as poor Galileo was, subject to the Inquisition for philosophical heresy. My whispers against the orthodox doctrine, in private letters, would be dangerous; but your writing and printing would be highly criminal. As it is, you must expect some censure; but one heretic will surely excuse another.
I am heartily glad to hear more instances of the success of the poke-weed in the cure of that horrible evil to the human body, a cancer. You will deserve highly of mankind for the communication. But I find in Boston they are at a loss to know the right plant, some asserting it is what they call mechoachan, others other things. In one of their late papers it is publicly requested that a perfect description may be given of the plant, its places of growth, &c. I have mislaid the paper, or would send it to you. I thought you had described it pretty fully. I am, Sir, &c.,
TO CADWALLADER COLDEN
Philadelphia, 14 May, 1752.
I find P—— has been indiscreet enough to print a piece in his paper which has brought him into a great deal of trouble. I cannot conceive how he was prevailed on to do it, as I know him to be a thorough believer himself, and averse to every thing that is commonly called freethinking. He is now much in his penitentials, and requests me to intercede with you, to procure from the governor a Nol. Pros. in his favor, promising to be very circumspect and careful for the future, not to give offence either in religion or politics, to you or any of your friends, in which, I believe, he is very sincere.
I have let him know that I pretend to no interest with you, and I fear he has behaved to the governor and to you in such a manner as not to deserve your favor. Therefore I only beg leave to recommend the poor man’s case to your consideration; and if you could, without inconvenience to your own character, interest yourself a little in his behalf, I shall, as I am much concerned for him, esteem it a very great obligation.
As to the cause of religion, I really think it will be best served by stopping the prosecution; for, if there be any evil tendency apprehended from the publication of that piece, the trial and punishment of the printer will certainly make it a thousand times more public,—such is the curiosity of mankind in these cases. It is, besides, an old thing, has been printed before both in England and by Andrew Bradford here; but, no public notice being taken of it, it died and was forgotten, as I believe it would now be, if treated with the same indifference. I am with great respect, &c.,
TO EDWARD AND JANE MECOM
Philadelphia, 21 May, 1752.
Dear Brother and Sister:
I received yours with the affecting news of our dear good mother’s death. I thank you for your long continued care of her in her old age and sickness. Our distance made it impracticable for us to attend her, but you have supplied all. She has lived a good life, as well as a long one, and is happy.
Since I sent you the order on Mr. Huske, I have received his account, and find he thinks he has money to receive, and though I endeavour by this post to convince him he is mistaken, yet possibly he may not be immediately satisfied, so as to pay that order; therefore, lest the delay should be inconvenient to you, I send the six pistoles enclosed. But if the order is paid, give those to brother John, and desire him to credit my account with them. Your affectionate brother,
TO JOHN PERKINS1
Philadelphia, 13 August, 1752.
I received your favor of the 3d instant. Some time last winter I procured from one of our physicians an account of the number of persons inoculated during the five visitations of the small-pox we have had in twenty-two years; which account I sent to Mr. W. V., of your town, and have no copy. If I remember rightly, the number exceeded eight hundred, and the deaths were but four. I suppose Mr. V. will show you the account, if he ever received it. These four were all that our doctors allow to have died of the small-pox by inoculation, though I think there were two more of the inoculated who died of the distemper; but the eruptions appearing soon after the operation, it is supposed they had taken the infection before in the common way.
I shall be glad to see what Dr. Douglass may write on the subject. I have a French piece printed at Paris, 1724, entitled Observations sur la Saignée duPied, et sur la Purgation, au Commencement de la Petite Vérole, et Raisons de doubte contre l’Inoculation. A letter of the Doctor’s is mentioned in it. If he or you have it not, and desire to see it, I will send it. Please to favor me with the particulars of your purging method, to prevent the secondary fever.
I am indebted for your preceding letter, but business sometimes obliges one to postpone philosophical amusements. Whatever I have wrote of that kind are really, as they are entitled, but Conjectures and Suppositions; which ought always to give place, when careful observation militates against them. I own I have too strong a penchant to the building of hypotheses; they indulge my natural indolence. I wish I had more of your patience and accuracy in making observations, on which alone true philosophy can be founded. And, I assure you, nothing can be more obliging to me than your kind communication of those you make, however they may disagree with my preconceived notions.
I am sorry to hear, that the number of your inhabitants decreases. I some time since wrote a small paper of Thoughts on the Peopling of Countries,1 which, if I can find, I will send you, to obtain your sentiments. The favorable opinion you express of my writings may, you see, occasion you more trouble than you expected from,
Sir, yours, &c.,
TO CADWALLADER COLDEN
Philadelphia, 14 September, 1752.
When I had read your favor of May the 20th, I resolved to read and consider more carefully Sir Isaac Newton’s Optics, which I have not looked at these many years. I delayed answering till I should have an opportunity of doing this, but one thing or other has hitherto hindered. In the winter I may possibly have more leisure.
In the mean time I would just mention that the interposition of a hill between a bell and the ear does interrupt a great part of the sound, though not all; and we cannot be certain that an opaque body placed between the eye and a luminous object intercepts all the light, since, as you observe, it does not follow that where we see no light there is therefore none existing. What you say of the separation of the distinct parts of light, which, once separated, remain always the same, has more weight with me, and indeed seems conclusive; at least, I see at present nothing to object.
I congratulate you on the prospect you have, of passing the remainder of life in philosophical retirement. I wish for the same, but it seems too distant. I might then more punctually perform my part in the correspondence you honor me with; than which I have none more instructive or agreeable.
Send me, if you please, the translation of your piece into High Dutch. I understand a little of the German language, and will peruse and return it. At present I cannot guess the meaning of the passage you mention. Unless perhaps, as your twentieth section speaks of “a power that neither resists nor moves, and exerts no kind of action of itself, without the concurrence of some other power; so that in the absence of other powers it must be in a perfect inaction,” &c., it may be some kind of Dutch wit, and intended to joke that quietism which in Germany is supposed to be very prevalent in Pennsylvania, many of their Quietists1 having removed hither.
I see by Cave’s Magazine for May that they have translated my electrical papers into French, and printed them in Paris. I hope our friend Collinson will procure and send me a copy of the translation. Such things should be done by men skilled in the subject as well as in the language, otherwise great mistakes are easily made, and the clearest matters rendered obscure and unintelligible.
TO PETER COLLINSON
read at the royal society, december 21, 1752
Philadelphia, 19 October, 1752.
As frequent mention is made in publick papers from Europe of the success of the Philadelphia experiment for drawing the electric fire from clouds by means of pointed rods of iron erected on high buildings, &c., it may be agreeable to the curious to be informed that the same experiment has succeeded in Philadelphia, though made in a different and more easy manner, which is as follows.
Make a small cross of two light strips of cedar, the arms so long as to reach to the four corners of a large thin silk handkerchief when extended; tie the corners of the handkerchief to the extremities of the cross, so you have the body of a kite; which, being properly accommodated with a tail, loop, and string, will rise in the air, like those made of paper; but this being of silk is fitter to bear the wet and wind of a thunder-gust without tearing. To the top of the upright stick of the cross is to be fixed a very sharp-pointed wire, rising a foot or more above the wood. To the end of the twine, next the hand, is to be tied a silk ribbon, and where the silk and twine join, a key may be fastened. This kite is to be raised when a thunder-gust appears to be coming on, and the person who holds the string most stand within a door or window, or under some cover, so that the silk ribbon may not be wet; and care must be taken that the twine does not touch the frame of the door or window. As soon as any of the thunderclouds come over the kite, the pointed wire will draw the electric fire from them, and the kite, with all the twine, will be electrified, and the loose filaments of the twine will stand out every way, and be attracted by an approaching finger. And when the rain has wetted the kite and twine, so that it can conduct the electric fire freely, you will find it stream out plentifully from the key on the approach of your knuckle. At this key the phial may be charged; and from electric fire thus obtained spirits may be kindled, and all the other electric experiments be performed which are usually done by the help of a rubbed glass globe or tube, and thereby the sameness of the electric matter with that of lightning completely demonstrated.
TO EDWARD AND JANE MECOM
Philadelphia, 14 November, 1752.
Dear Brother and Sister:
Benny sailed from hence this day two weeks, and left our Capes the Sunday following. They are seldom above three weeks on the voyage to Antigua.
That island is reckoned one of the healthiest in the West Indies. My late partner there enjoyed perfect health for four years, till he grew careless, and got to sitting up late in taverns, which I have cautioned Benny to avoid, and have given him all other necessary advice I could think of, relating both to his health and conduct, and I hope for the best.
He will find the business settled to his hand: a newspaper established, no other printing-house to interfere with him, or beat down his prices, which are much higher than we get on the continent. He has the place on the same terms with his predecessor, who, I understand, cleared from five to six hundred pistoles during the four years he lived there. I have recommended him to some gentlemen of note for their patronage and advice.
Mr. Parker, though he looked on Benny as one of his best hands, readily consented to his going, on the first mention of it. I told him Benny must make him satisfaction for his time. He would leave that to be settled by me, and Benny as readily agreed with me to pay Mr. Parker as much as would hire a good journeyman in his room. He came handsomely provided with apparel, and I believe Mr. Parker has, in every respect, done his duty by him, and in this affair has really acted a generous part; therefore I hope, if Benny succeeds in the world, he will make Mr. Parker a return beyond what he has promised. I suppose you will not think it amiss to write Mr. and Mrs. Parker a line or two of thanks; for, notwithstanding some little differences, they have on the whole been very kind to Benny.
We have vessels going very frequently from this port to Antigua. You have some too from your port. What letters you send this way I will take care to forward. Antigua is the seat of government for all the Leeward Islands, to wit, St. Christopher’s, Nevis, and Montserrat. Benny will have the business of all those islands, there being no other printer.
After all, having taken care to do what appears to be for the best, we must submit to God’s providence, which orders all things really for the best.
While Benny was here, and since, our Assembly was sitting, which took up my time, and I could not before write you so fully.
With love to your children, I am, dear brother and sister, your affectionate brother,