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LXVIII: TO PETER COLLINSON - Benjamin Franklin, The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753 [1904]

Edition used:

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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LXVIII

TO PETER COLLINSON

Magical Circle

Sir:—

I am glad the perusal of the magical squares afforded you any amusement. I now send you the magical circle. (See Plate V.)

Its properties, besides those mentioned in my former, are these:

Half the numbers in any radial row added with half the central number, make 180, equal to the number of degrees in a semicircle.

Also half the numbers in any one of the concentric circles, taken either above or below the horizontal double line, with half the central number, make 180.

And if any four adjoining numbers, standing nearly in a square, be taken from any part and added with half the central number, they make 180.

There are, moreover, included four other sets of circular spaces, eccentric with respect to the first, each of these sets containing five spaces. The centres of the circles that bound them, are at A, B, C, and D. Each set, for the more easy distinguishing them from the first, are drawn with a different colored ink, red, blue, green, and yellow.1

These sets of eccentric circular spaces intersect those of the concentric, and each other, and yet the number contained in each of the twenty eccentric spaces, taken all around, make, with the central number, the same sum as those in each of the eight concentric, viz., 360. The halves also of those drawn from the centres A and C, taken above or below the double horizontal line, and of those drawn from centres B and D taken to the right or left of the vertical line, do, with half the central number, make just 180.

It may be observed, that there is not one of the numbers but what belongs at least to two of the different circular spaces; some to three, some to four, some to five; and yet they are all so placed as never to break the required number 360, in any of the twenty-eight circular spaces within the primitive circle.

These interwoven circles make so perplexed an appearance, that it is not easy for the eye to trace every circle of numbers one would examine, through all the maze of circles intersected by it; but if you fix one foot of the compasses in either of the centres, and extend the other to any number in the circle you would examine belonging to that centre, the moving foot will point the others out, by passing round over all the numbers of that circle successively. I am, &c.,

B. Franklin.

LXIX

TO JARED ELIOT

Philadelphia, 13 February, 1750.

Dear Sir:

You desire to know my thoughts about the northeast storms beginning to leeward. Some years since, there was an eclipse of the moon at nine o’clock in the evening, which I intended to observe; but before night a storm blew up at northeast, and continued violent all night and all next day; the sky thick-clouded, dark, and rainy, so that neither moon nor stars could be seen. The storm did a great deal of damage all along the coast, for we had accounts of it in the newspapers from Boston, Newport, New York, Maryland, and Viriginia; but what surprised me was to find in the Boston newspapers an account of an observation of that eclipse made there; for I thought, as the storm came from the northeast, it must have begun sooner at Boston than with us, and consequently have prevented such observation. I wrote to my brother about it, and he informed me, that the eclipse was over there an hour before the storm began. Since which I have made inquiries from time to time of travellers, and of my correspondents northeastward and southwestward, and observed the accounts in the newspapers from New England, New York, Maryland, Virginia, and South Carolina; and I find it to be a constant fact, that northeast storms begin to leeward, and are often more violent there than farther to windward. Thus the last October storm, which with you was on the 8th, began on the 7th in Virginia and North Carolina, and was most violent there.1

As to the reason of this, I can only give you my conjectures. Suppose a great tract of country, land and sea, to wit, Florida and the Bay of Mexico, to have clear weather for several days, and to be heated by the sun, and its air thereby exceedingly rarefied. Suppose the country northeastward, as Pennsylvania, New England, Nova Scotia, and Newfoundland, to be at the same time covered with clouds, and its air chilled and condensed. The rarefied air being lighter must rise, and the denser air next to it will press into its place; that will be followed by the next denser air, that by the next, and so on. Thus, when I have a fire in my chimney, there is a current of air constantly flowing from the door to the chimney; but the beginning of the motion was at the chimney, where the air being rarefied by the fire rising, its place was supplied by the cooler air that was next to it, and the place of that by the next, and so on to the door. So the water in a long sluice or mill-race, being stopped by a gate, is at rest like the air in a calm; but as soon as you open the gate at one end to let it out, the water next the gate begins first to move, that which is next to it follows; and so, though the water proceeds forward to the gate, the motion which began there runs backwards, if one may so speak, to the upper end of the race, where the water is last in motion. We have on this continent a long ridge of mountains running from northeast to southwest, and the coast runs the same course. These may, perhaps, contribute towards the direction of the winds, or at least influence them in some degree. If these conjectures do not satisfy you, I wish to have yours on the subject.

I doubt not but those mountains which you mention contain valuable mines, which time will discover. I know of but one valuable copper mine in this country, which is that of Schuyler’s in the Jerseys. This yields good copper, and has turned out vast wealth to the owners. I was at it last fall, but they were not then at work. The water is grown too hard for them, and they waited for a fire-engine from England to drain their pits. I suppose they will have that at work next summer; it costs them one thousand pounds sterling.

Colonel John Schuyler, one of the owners, has a deer park five miles round, fenced with cedar logs, five logs high, with blocks of wood between. It contains a variety of land, high and low, woodland and clear. There are a great many deer in it, and he expects in a few years to kill two hundred head a year, which will be a very profitable thing. He has likewise six hundred acres of meadow, all within bank. The mine is not far from Passaic Falls, which I went also to see. They are very curious; the water falls seventy feet perpendicularly, as we are told; but we had nothing to measure with.

It will be agreeable to you to hear that our subscription goes on with great success, and we suppose will exceed five thousand pounds of our currency. We have bought for the Academy the house that was built for itinerant preaching, which stands on a large lot of ground capable of receiving more buildings to lodge the scholars, if it should come to be a regular college. The house is one hundred feet long and seventy wide, built of brick, very strong, and sufficiently high for three lofty stories. I suppose the building did not cost less than two thousand pounds but we bought it for seven hundred and seventy-five pounds, eighteen shillings, eleven pence, and three farthings; though it will cost us three and perhaps four hundred more to make the partitions and floors and fit up the rooms. I send you enclosed a copy of our present constitution but we expect a charter from our Proprietaries this summer, when they may probably receive considerable alterations. The paper admonishes me that it is time to conclude.

I am, Sir,
Your obliged humble servant,

B. Franklin.