Page:Memoir, correspondence, and miscellanies, from the papers of Thomas Jefferson - Volume 1.djvu/406

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LETTER CXLVII.

TO F. HOPKINSON.

Paris, January 3, 178G. DEAR SIR,

I wrote you last, on the 25th of September. Since that, I have received yours of October the 25th, enclosing a duplicate of the last invented tongue for the harpsichord. The letter enclosing another of them, and accompanied by newspapers, which you mention in that of October the 25th, has never come to hand. I will embrace the first opportunity of sending you the crayons. Perhaps they may come with this, which I think to deliver to Mr. Bingham, wiio leaves us on Saturday, for London. If, on consult ing him, I find the conveyance from London uncertain, you shall receive them by a Mr. Barrett, who goes from hence for New York, next month. You have not authorised me to try to avail you of the new tongue. Indeed, the ill success of my endeavors with the last, does not promise much with this. However, I shall try. Houdon only stopped a moment, to deliver me your letter, so that I have not yet had an opportunity of asking his opinion of the improvement. I am glad you are pleased with his work. He is among the foremost, or, perhaps, the foremost artist in the world.

Turning to your Encyclopedic, Arts et Metiers, tome 3, part 1, page 393, you will find mentioned an instrument, invented by a Monsieur Renaudin, for determining the true time of the musical movements, largo, adagio, &c. I went to see it. He shewed me his first invention ; the price of the machine was twenty-five gui neas : then his second, which he had been able to make for about half that sum. Both of these had a mainspring and a balance wheel, for their mover and regulator. The strokes were made by a small hammer. He then shewed me his last, which is moved by a weight and regulated by a pendulum, and which cost only two guineas and a half. It presents, in front, a dial plate like that of a clock, on which are arranged, in a circle, the words largo, adagio, andante, allegro, presto. The circle is moreover divided into fifty-two equal degrees. Largo is at 1, adagio at 11, andante at 22, allegro at 36, and presto at 46. Turning the index to any one of these, the pendulum (which is a string, with a ball hanging to it) shortens or lengthens, so that one of its vibrations gives you a crotchet for that movement. This instrument has been examin ed by the academy of music here, who are so well satisfied of its utility, that they have ordered all music which shall be printed