“ cured it for me from a library in Philadelphia. but on perusal of it, his plan of two pendulums appeared to me on the whole less eligible than Leslie’s of the vibrating rod.--how has it been inferred that S ^r. Isaac Newton’s calculation of the length of the pendulum for the latitude of London is 39.2 Inches? from his general table in the Principia. B. 3. I deduce 39.1682. am I wrong? if so, I may be equally wrong in the calculation of 39.1285 I. for lat. 38 ^o. in which an error would be fundamentally important, & therefore I ask your peculiar attention to that. what do you think of the vibrating rod? is it not clear of some objections which lie against the pendulum? and is it liable to any of which that is clear? and which is best on the whole?--I am too little familiar with the mechanism of the clock to know how the rod can be adapted to a machinery which shall maintain and count it’s vibrations, without accelerating them by it’s power, or retarding them by it’s frcition, in short which shall leave the rod free to make it’s vibrations uninfluenced by any circumstance but it’s own length. on this point no man in the world can judge or contrive better than yourself. on this then and all the other parts of the report pray give me the full benefit of your assistance. in the trouble I am giving you I feel it as a circumstance of additional misfortune that I am pressed in time. the session of Congress is drawing to a close. nothing will keep them together after the money bills are got through, & this will be pretty soon. I am obliged therefore to ask your immediate attention to this subject, as I must give in the report before they rise. I suppose they will have it printed for consideration, to be taken up at their next meeting.

" I will not weary you with apologies, tho I feel powerfully the necessity of them . . .”

On the same day he had written to Alexander Hamilton, the Secretary of the Treasury: “ M ^r. Jefferson presents his compliments to the Secretary of the Treasury, and asks his perusal of the inclosed rough draught of a report on the subject of measures, weights & coins, in hopes that the Secretary of the Treasury may be able to accomodate his plan of a mint to the very small alteration of the money unit proposed in this report. as soon as the Secretary of the Treasury shall have read it, m ( ^~ r) Jefferson asks the favor of him to return it, as he wishes to submit it to the examination and correction of some mathematical friends. ”

Hamilton replied in a note dated only Wednesday: “M ^r. Hamilton presents his Compliments to M ^r. Jefferson. He has perused with much satisfaction the draft of his report on the subject of weights and measures. There is no view which M ^r. H. has yet taken of the matter which stands opposed to the alteration of the money-unit as at present contemplated by the regulations of Congress either in the way suggested in the report or in that mentioned in the note of yesterday--And there are certainly strong reasons to render a correspondency desireable. The idea of a general standard among nations, as in the proposal of the Bishop d’Autun seems full of convenience & order.”

On June 14 Jefferson received from William Short the Proposition of the Bishop of Autun [q.v. no. 3761], which necessitated changes in this Report. He wrote on the same day to David Rittenhouse: “ I inclosed you, the day before yesterday a rough draught of the report I had prepared on the subject of weights & measures. I have this morning recieved from m ( ^~ r) Short a proposition made by the Bishop of Autun to the National assembly of France on the same subject, which I inclose you, & will beg the favor of you to return it by post after you shall have perused it. he mentions that the lat. of 45 ^o. as being a middle term between the Equator & pole had been proposed as the general standard for measures, and he makes the proposition anew, & desires it should be made to England. as this degree of Latitude is our Northern boundary, as it may form a link between us & Europe, and as the degree which shall give the standard is not otherwise very material, I have thought of proposing it in my report instead of the 38 ^th. degree. I have in consequence gone over my calculations again upon the ground of a pendulum of 36-- ^pouces 8.428 ^lignes (S ^r Isaac Newton’s calculation for 45 ^o.)=39.14912 inches giving a rod of 58.72368 inches, and reformed the tables (last page of the report) of which reformation I send you a copy. the alterations in the body of the work may be easily made from this. the bishop sais the pendulum has been calculated for 45 ^o. to be ”