Thomas Jefferson Papers

From Thomas Jefferson to Thomas Cooper, 27 October 1808

Washington Oct. 27. 08.

Dear Sir

When I recieved your letter of the 16th. I thought I had not a copy of my Report on Measures, weights & coins, except one bound up in a volume with other reports. but on carefully searching a bundle of duplicates, I found the one I now inclose you, being the only detached one I possess. it is defective in one article. the report was composed under a severe attack of periodical head ach which came on every day at Sunrise, & never left me till sunset. what had been ruminated in the day under a paroxysm of the most excruciating pain was committed to paper by candle light, & then the calculations were made. after delivering in the report it was discovered that in calculating the money unit §.5. pa. 49. there was a small error in the 3d. or 4th. column of decimals, the correction of which however brought the proposed unit still nearer to the established one. I reported the correction in a single leaf to Congress. the copy I sent you has not that leaf.

The first question to be decided is between those who are for Units of measures, weights & coins having a known relation to something in nature of fixed dimension, and those who are for an arbitrary standard. on this diu vexata quaestio it is useless to say a word, every one having made up his mind on a view of all that can be said. mr Dorsey was so kind as to send me his pamphlet, by which I found he was for the arbitrary standard of one third of the standard yard of H. I. of England, supposed to be in the Exchequer of that nation, a fac simile of which was to be procured & lodged in Philadelphia I confess myself to be of the other sect, and to prefer an Unit bearing a given relation to some fixed subject of nature, & of preference to the pendulum because it may be in possession of every man, so that he may verify his measures for himself. you will observe that I proposed alternative plans to Congress, that they might take the one or the other according to the degree of courage they felt. the 1st. is from pa. 18. to 38. the 2d. from pa. 39. to 44. were I now to decide it would be in favor of the first, with this single addition, that each of the denominations there adopted should be divisible decimally at the will of every individual. the Iron founder deals in tons. let him take the ton for his Unit, & divide it into 10ths. 100ths. 1000ths. the dry good merchant deals in pounds, & yards. let him divide them decimally. the land measurer deals in miles & poles. divide them decimally, only noting over his figures that the Unit is, thus. 18.943 tons—18.943 lb—1.8943 yds—189.43 miles Etc. I have lately had a proof how familiar this division into dimes, cents & mills is to the people when transferred from their money to any thing else. I have an Odometer fixed to my carriage which gives the distances in miles, dimes & cents. the people on the road enquire with curiosity what exact distance I have found from such a place to such a place, I answer, so many miles, so many cents. I find they universally & at once form a perfect idea of the relation of the cent to the mile as an unit. they would do the same as to yards of cloth, pounds of shot, ounces of silver or of medecine. I believe therefore they are susceptible of this degree of approximation to a standard rigorously philosophical. beyond this I might doubt. however on this too every one has an opinion, and I am open to compromise, as I am also to other plans of reformation of which multitudes have been published. I can conclude therefore candidly with the si quid noviste rectius Etc and sincerely with assurances of my constant esteem & respect.

Th: Jefferson

DLC: Papers of Thomas Jefferson.

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