“ ainsi que de la lettre que j’ai l’honneur de vous ecrire . . .

"Je souhaite que cet ouvrage soit acceuilli favorablement, par la Societé philosophique de Philadelphia, à laquelle aucun genre de connoissances, n’est étrange ni indifferent: et si le changement des poids et mesures, a lieu dans les Etats-unis, comme vous le laissez voir, Monsieur, je désirerois par le sincere attachement que m’a inspiré le grand exemple de conquérir la liberté, qu’a donné à l’univers, le sage et le courageux peuple de vos regions occidentales, je désirerois dis-je pouvoir y contribuer efficacement . . .”

Rigobert Bonne, 1727-1794, French geographer.

This manuscript is not in the Library of Congress and has not been found.

Jefferson’s copy was sent to him shortly after publication by James Somerville, to whom Jefferson wrote from Philadelphia on December 1, 1791: “ I am to acknolege the receipt of your favour covering one of Keith’s pamphlets on Weights & measures, which contains a great deal of information on the subject. with my thanks be pleased to accept assurances of the regard with which I have the honor to be . . . ”

On June 8 of the following year, 1792, Jefferson wrote to David Rittenhouse, at the time director of the mint, and president of the American Philosophical Society: “ Th: Jefferson incloses to m( ^~ r) Rittenhouse the first criticism which has come to his hands on the rod-pendulum as a standard of measure. it is from a clergyman of Scotland. the author’s language is so lax, that it is difficult to know with precision what idea he means to express. it is particularly so in the following sentence at the bottom of the 1 ^st. page. ‘it is therefore impossible to fix an invariable, or nearly equal measure from the rod of such a cylindrical pendulum--for, measured from the extremities, a second’s pendulum is of all possible lengths from 39 to 58½ inches.’--in a preceding passage where he says that ‘the length of the pendulum has nothing to do with the whole length of the rod.’ he cannot possibly mean what he says. that they are the same thing, nobody ever pretended; but that, in theory, they have a determinate relation of 2 to 3. to one another, nobody can deny.--he says again pa. 2. ‘no philosopher who has studied the doctrine of the Pendulum ever measured it from it’s extremities.’ why this observation? Th: J. had made the difficulty, in a bob-pendulum of finding the center of oscillation, from which it was to be measured, one reason for rejecting the bob-pendulum, & adopting the rod & pendulum which admits of being measured from the extremities, because in this one extremity may be made the center of motion.--what does he mean by saying that the difference between the cubic foot proposed by Th: J. and the English cubic foot (which Th: J. had stated to be 1/14 as m ( ^~ r) Skene does) ‘is a monstrous error’?--if m( ^~ r) Rittenhouse can find out what m( ^~ r) Skene means to object and will favor Th: J. with his thoughts on it, he will thank him.”