Benjamin Franklin Papers

To Benjamin Franklin from James Bowdoin, 2 March 1752

From James Bowdoin

Copy: Massachusetts Historical Society8

Boston March 2d. 1752


I have received your favour of the 24th. January past,9 inclosing an Extract from your Letter to Mr. Collinson and Dr. Colden’s Letter to yourself,1 which I have read with a great deal of pleasure, and am much obliged to you for. Your Extract confirms a correction Mr. Kinnersley made a few days ago of a mistake I was under respecting the polarity given to needles by the electrical fire “that the end which receives the fire always points north” and “that the needle being Situated East and West, will not have a polar direction.” You find however the polarity strongest when the needle is shock’d lying North and South; weakest when lying East and West: which makes it probable that the communicated magnetism is less, as the needle varies from a North and South Situation. As to the needle of Capt. Waddel’s Compass;2 if it’s polarity was reversed by the Lightning, the effect of Lightning and Electricity in regard of that, seems dissimilar: for a magnetic needle in a North and South Situation (as the Compass-needle was) instead of having it’s power reversed or even diminished, would have it confirmed or increased by the electrical fire. But perhaps the Lightning communicated to some nails in the Binocle (where the Compass is placed) the magnetic virtue, which might disturb the Compass. This I have heard was the case; if so, this seeming dissimilarity vanishes. But this remarkable Circumstance (if it took place) I should think would not be omitted in Capt. Waddel’s Account. I am very much pleased, that the Explication I sent you of the crooked direction of Lightning meets with your approbation. As to your Supposition about the Source of Lightning, the luminous appearance of the Sea in the night, and the Similitude between the friction of the particles of Salt and Water as you considered them in their original Separate State, and the friction of the Globe and Cushion, very naturally led you to the Ocean as the grand Source of Lightning. But the activity of Lightning or the electric Element, and the fitness of water to conduct it, together with the Experiments you mention of Salt and Water seem to make against it, and to prepare the way for some other hypothesis. Accordingly you propose a new one, which is very curious, and not so liable I think to objections as the former; but there is not as yet I believe a sufficient variety of Experiments to establish any Theory, tho’ this is3 the most hopeful of any I have heard of. The Effect which the discharge of your four Glass Jars had upon a fine wire ty’d between two strips of Glass, puts me in mind of one very similar of Lightning, that I observed at New York October 1750, a few days after I left Philadelphia.

In company with a number of Gentlemen I went to take a view of the City from the Dutch Church Steeple, in which is a Clock about 20, or 25 feet below the Bell.4 From the Clock went a wire thro’ two floors to the Clock Hammer near the Bell: the holes in the floors for the wire being about ¼ of an inch Diameter. We were told that in the Spring of 1750 the Lightning struck the Clock-Hammer, and descended along the wire to the Clock, melting in its way several Spots of the wire from three to nine inches long thro’ one third of its Substance, till coming within a few feet of the lower end it melted the wire quite thro’ in several places, so that it fell down in several pieces; which spots and pieces we saw.

When it got to the End of the wire, it flew off to the hindge of a door, shattered the door and dissipated. In its passage thro’ the holes of the floors it did not do the least damage: which evidences that wire is a good conducter of Lightning (as it is of Electricity) provided it be substantial enough, and might in this case, had it been continued to the Earth, have conducted it without damaging the building.5 Your information about your Globe raising electrical fire in greater Quantity by means of wire extended from the Cushion to the Earth, will enable me, I hope, to remedy a great inconvenience I have been under to collect the fire with the electrifying Glass I use, which is fixed in a very dry room three Stories from the ground. When you send your Meteorological Observations to Dr. Perkins I hope I shall have the pleasure of seeing them. I heartily congratulate you on your Advancement in public Life,6 but I hope it will not be the means of diverting your tho’ts from philosophical subjects, which would be a real injury (I speak it without flattery) to the philosophical world. With the greatest respect I am Yours &c.

P.S. As it may be pleasing to your Brother and Mr. Kennersley to see Dr. Colden’s Letter, I take the Liberty (which I hope you’ll think excusable) to detain it till next post.

[Note numbering follows the Franklin Papers source.]

8Letter XV in 1769 and 1774 editions of Exper. and Obser. Read in the Royal Society, June 3, 1756.

9Not found.

1The letter to Collinson is printed above, pp. 143–5; that from Colden has not been found, but it dealt with the subject of his letter to BF, March 16, 1752 (see below, p. 277).

2John Waddell reported in Phil. Trans., XLVI (1749–50), 111–12, that his ship, bound from New York to London, was struck by lightning, Jan. 9, 1749; all four compasses aboard were demagnetized.

3In 1769 and 1774 editions: “seems” replaces “is.”

4With Rev. Samuel Cooper and Peter Etter of Boston, Bowdoin visited the New Dutch (later known as the Middle Dutch) Church, built 1729–31, whose steeple was a favorite place to take visitors for a view of the city. It was frequently struck by lightning, 1732–65, and a lightning rod was erected, 1763. I. N. Phelps Stokes, The Iconography of Manhattan Island (N.Y., 1915–28), IV, 528, 590, 622, 718, 735, 749.

5Note in 1769 and 1774 editions: “The wire mentioned in this account was re-placed by a small brass chain. In the summer of 1763, the lightning again struck that steeple, and from the clock-hammer near the bell, it pursued the chain as it had before done the wire, went off to the same hinge, and again shattered the same door. In its passage through the same holes of the same floors, it did no damage to the floors, nor to the building during the whole extent of the chain. But the chain itself was destroyed, being partly scattered about in fragments of two or three links melted and stuck together, and partly blown up or reduced to smoke, and dissipated. [See an account of the same effect of lightning on a wire at Newbury, p. 163.] The steeple, when repair’d, was guarded by an iron conductor, or rod, extending from the foot of the vane-spindle down the outside of the building, into the earth. The newspapers have mentioned, that in 1765, the lightning fell a third time on the same steeple, and was safely conducted by the rod; but the particulars are not come to hand.” Brackets in the printed version; the reference is to a letter from BF to Dalibard, June 29, 1755, printed in Exper. and Obser., 1769 edit., p. 163.

6BF was elected to the Pennsylvania Assembly, October 1751. This sentence and the postscript were omitted from the printed editions.

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