SIR,--I thank you for the communication of Mr. Jonathan Ellicot's letter in yours of August 28th, and the information it conveys. With respect to mine of August 13th, I do not know that it contains anything but what any man of mathematical reading may learn from the same sources; however, if it can be used for the promotion of right, I consent to such an use of it. Your inquiry as to the date of Martin's invention of the drill plough, with a leathern band and metal buckets, I cannot precisely answer; but I received one from him in 1794, and have used it ever since for sowing various seeds, chiefly peas, turnips, and benni. I have always had in mind to use it for wheat; but sowing only a row at a time, I had proposed to him some years ago to change the construction so that it should sow four rows at a time, twelve inches apart; and I have been waiting for this to be done either by him or myself; and have not, therefore, commenced that use of it. I procured mine at first through Col. John Taylor of Caroline, who had been long in the use of it, and my impression was that it was not then a novel thing. Mr. Martin is still living, I believe. If not, Colonel Taylor, his neighbor, probably knows its date. If the bringing together under the same roof various useful things before known, which you mention as one of the grounds of Mr. Evans' claim, entitles him to an exclusive use of all these, either separately or combined, every utensil of life might be taken from us by a patent. I might build a stable, bring into it a cutting-knife to chop straw, a hand-mill to grind the grain, a curry comb and brush to clean the horses, and by a patent exclude every one from ever more using these things without paying me. The elevator, the conveyer, the hopper-boy, are distinct things, unconnected but by juxtaposition. If no patent can be claimed for any one of these separately, it cannot be for all of them,--several nothings put together cannot make a something;--this would be going very wide of the object of the patent laws. I salute you with esteem and respect. TO MR. JAMES MARTIN. MONTICELLO, September 20, 1813.