DEAR SIR,--The enclosed work came to me without a scrip of a pen other than what you see in the title-page--"A Monsieur le President de la Société." From this I conclude it intended for the Philosophical Society, and for them I now enclose it to you. You will find the notes really of value. They embody and ascertain to us all the scraps of new discoveries which we have learned in detached articles from less authentic publications. M. Goudin has generally expressed his measures according to the old as well as the new standard, which is a convenience to me, as I do not make a point of retaining the last in my memory. I confess, indeed, I do not like the new system of French measures, because not the best, and adapted to a standard accessible to themselves exclusively, and to be obtained by other nations only from them. For, on examining the map of the earth, you will find no meridian on it but the one passing through their country, offering the extent of land on both sides of the 45th degree, and terminating at both ends in a portion of the ocean which the conditions of the problem for an universal standard of measures require. Were all nations to agree therefore to adopt this standard, they must go to Paris to ask it; and they might as well long ago have all agreed to adopt the French foot, the standard of which they could equally have obtained from Paris. Whereas the pendulum is equally fixed by the laws of nature, is in possession of every nation, may be verified everywhere and by every person, and at an expense within every one's means. I am not therefore without a hope that the other nations of the world will still concur, some day, in making the pendulum the basis of a common system of measures, weights and coins, which applied to the present metrical systems of France and of other countries, will render them all intelligible to one another. England and this country may give it a beginning, notwithstanding the war they are entering into. The republic of letters is unaffected by the wars of geographical divisions of the earth. France, by her power and science, now bears down everything. But that power has its measure in time by the life of one man. The day cannot be distant in the history of human revolutions, when the indignation of mankind will burst forth, and an insurrection of the universe against the political tyranny of France will overwhelm all her arrogations. Whatever is most opposite to them will be most popular, and what is reasonable therefore in itself, cannot fail to be adopted the sooner from that motive. But why leave this adoption to the tardy will of governments who are always, in their stock of information, a century or two behind the intelligent part of mankind, and who have interests against touching ancient institutions? Why should not the college of the literary societies of the world adopt the second pendulum as the unit of measure on the authorities of reason, convenience and common consent?