Benjamin Franklin Papers

To Benjamin Franklin from Thomas Gilpin, 16 May 1769

From Thomas Gilpin5

Reprinted from “Memoir of Thomas Gilpin,” Pennsylvania Magazine of History and Biography, XLIX (1925), 304.

Philadelphia May 16th. 1769.

Worthy Friend

By the brig Ketly Capt. Osborne I have sent you the model of a machine the result of a thought occurring to me some time ago which I have realised in the present form. It is that of an horizontal windmill applied to three pumps——this application as one of the most useful for raising water from lands, draining mines or pumping ships in distress at sea; but if the first movement be found effective it may be applied to all the various uses of other windmills, without the inconvenience of turning the house or frame to the wind. I could mention some further objects that have occurred to me on the subject but I daresay they will present themselves to you; when you have examined the model if you think the invention of sufficient importance I would thank you to have it shewn to the Society of Arts or made public in any way you may think it merits.6 The necessity of regulating and stopping the motion of the mill will no doubt occur to you; that part of it I have omitted at present from want of time, but it is very easy, nearly as much so as that of stopping a water mill and I shall have it fixed to another model I am preparing for the Philosophical Society here.7 Your sentiments on this invention at a leisure moment will be very gratifying and esteemed a particular favor by your friend

Thomas Gilpin.

P.S. I have an idea that this machine with some alterations would answer well in a current of water.

[Note numbering follows the Franklin Papers source.]

5See the headnote of Gilpin to BF above, Jan. 29.

6BF promised in July to exhibit the pump at the November meeting of the Society of Arts, but did not do so until the following spring, when he said he was about to meet with a committee to explain its workings. See his letters to Gilpin below, July 10, 1769, and March 18, 1770.

7A short description of the machine was published in the APS Trans., I (1771), 339.

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