Thomas Jefferson Papers

To Thomas Jefferson from David K. Hopkins, 26 September 1808

City of Washing
Sept 26th 1808.


in the winter of 1806, you may recollect of my visiting you at the Presidents palace; & that without a previous acquaintance, or letters of introduction the reason was, that I thought the introduction wou’d be as Satisfactory on both parts, by the Subject alone as by letters: Mr Dufief particularly offered me a letter, but I considdered it intirely unnessary for the reason before mentioned; he then told me that he had no introduction. & Sir I believe it made kind of difference.—if you recollect my purpose was, to make an improvement on the mode of Communicateing motion: at that time I thought I had Compleated it, but Since I have found that I only Commenced it, for, not untill lately have I brought the affair to a Close.—I now prepose a revolution in the present System of Communicating motion; & if my principles be Correct it also will produce a revolution in the System of Mechanics—as far as I have experimented my principle is Correct; on the windmill particularly I have applied the principle to the Sails, & from that alteration I find that Twenty yards less will answer in the hundred the Same purpose. I have not applied it as runing gear to my windmill, but I have to a grindstone with equal effect.—the Screw is the power with which I produe motion to the most advantag in every Case, either by water, wind, Steam, or in any other way that motion is to be produced. I will Say no more on the Subject now, but hope & pray that you will give me permission to lay the whole before you.—I have been on the Subject of Mechanics for more than Six years; your knowledge of geneal principles is So extensive, that I know I Should receive more Satisfaction in communicating with you than any other person in the world Should I be mistaken I wish to know it & if I am not, I wish to know it also. if through any motive whatever you Should decline answering me, I Should never forgive my self for writing to you. figure to your Self a young man Scarcely more than Twenty five years of age, who has been, & Continues be anxious to benefit Philosophy, who has Secluded himself from the world & devoted himself to its Study. Mr Dufief told me that you were always ready to correspond with or See, a deep thinking man; I am Confident I am one of that Class, whether my thoughts will turn to the advantage of Society or not. be Assured that no man esteems your Excellency more than I do.

David K. Hopkins

NB. if you write, have the goodness to direct it to the care of Matthew Hopkins Esqr Snow Hill Maryland.

D. K. Hopkins

DLC: Papers of Thomas Jefferson.

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