I have to acknolege the reciept of your favor of Dec. 20. and am much pleased to find our progress in manufactures to be so great. that of cotton is peculiarly interesting, because we raise the raw material in such abundance, and because it may to a great degree supply our deficiencies both in wool & linen. a former application on behalf of Messrs. Binney & Robertson was delivered to the Secretary of State, who will engage Genl. Armstrong to aid such measures as they may take in Paris for obtaining permission to draw supplies of Antimony from thence.

It will give me real pleasure to see some good system of measures & weights introduced and combined with the decimal arithmetic. it is a great & difficult question whether to venture only on a half reformation, which by presenting fewer innovations may be more easily adopted, or, as the French have tried with success, make a radical reform. your plan presents as few innovations as any I have seen; but I think your foot should refer to the pendulum (by saying for instance that the foot shall be a measure which shall be to the second pendulum as 1. to 3.267 or rather as 1. to the length of a pendulum vibrating seconds in 1at. 45°. this offers a standard in every place, because it can every where be found. the rod you propose is only to be found in Philadelphia. you say in your letter that ‘if the decimal mode obtain in the division of the ℔, the Troy & it, as regards the Troy grain would be the same’. I do not understand this, because the avoirdupoise ℔ containing 7000. troy grains, I do not see how any decimal subdivision of the ℔ could coincide with the Troy grain. however I shall be very glad to see adopted whatever measure is most promising. I salute you with esteem & respect.