To A. D. Saunders
Monticello July 31. 16.
I have just recieved your favor of June 26. mentioning your invention of a horizontal wheel so constructed as that it’s gravity shall make it continue to seek it’s resting place, yet never to change it’s position, and enquiring whether I know of any thing of the kind in this or any other country. I know of no such thing any where; and as what is said leaves an idea of impossibility, so I must suppose there is something not said which would remove the impossibility. I would certainly advise you to trust to no demonstrations on paper, nor conceptions of the mind, but to execute the thing in large & see it work before you commit yourself to the public. the effects of friction & imperfection of workmanship must exhaust some power & are beyond calculations & conceptions.
I think our state has never given a patent for any invention since the federal constitution gave that power to Congress. were they to do it it might produce conflict and question between the two authorities. but the Congressional law altho’ it involves the people in dangers and impositions, seems abundantly to secure to the patentee his own principle. another may improve upon the principle; yet he cannot use the principle itself without paying for it. he cannot add his improvement till he has purchased the use of the principle on which it is engrafted.
PoC (MHi); at foot of text: “Mr A. D. Saunders”; endorsed by TJ.
Article I, section 8 of the United States constitution gives Congress the power to issue patents. The patent law was “An Act to promote the progress of useful Arts; and to repeal the act heretofore made for that purpose,” 21 Feb. 1793, which was modified in 1800 to extend the right of patenting to foreign nationals with two years’ residency (U.S. Statutes at Large description begins Richard Peters, ed., The Public Statutes at Large of the United States … 1789 to March 3, 1845, 1845–67, 8 vols. description ends , 1:318–23, 2:37–8).