Thomas Jefferson Papers

From Thomas Jefferson to John Churchman, 8 August 1787

To John Churchman

Paris Aug. 8. 1787.


I have duly received your favor of June 6. and immediately communicated it’s contents to a member of the Academy. He told me they had received the other copy of your memorial which you mention to have sent thro’ another channel, that your ideas were not conveyed so explicitly as to enable them to decide finally on their merit, but that they had made an entry in their journals to preserve to you the claim to the original idea. As far as we can conjecture it here, we imagine you make a table of variations of the needle for all the different meridians whatever. To apply this table to use in the voiage between America and Europe, suppose the variation to increase a degree in every 160 miles, two difficulties occur. 1. A ready and accurate method of finding the variation of the place. 2. An instrument so perfect as that (tho’ the degree on it shall represent 160 miles) it shall give the parts of the degree so minutely as to answer the purposes of the navigator. The variation of the needle at Paris actually is 21°. W. I make no doubt but you have provided against the doubts entertained here, and I shall be happy that our country may have the honour of furnishing the old world what it has so long sought in vain. I am with much respect Sir Your most obedient humble servt.,

Th: Jefferson

PrC (DLC); at foot of text: “Mr. John Churchman Philadelphia.” The RC is described in the Catalogue of the Alfred Morrison Autograph Collection (NN), but has not been found.

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