Your letter of Nov. 26. came to hand May 14. the books some time after; which were all distributed according to direction. the copy for the E. Indies went immediately by a safe conveyance. the letter of Apr. 28. & the copy of your work accompanying that did not come to hand till August. that copy was deposited in the Congressional library. it was not till my return here from my autumnal visit to Monticello that I had an opportunity of reading your work. I have read it, and with great satisfaction. of the first part, I am less a judge than most people, having never travelled Westward of Stanton, so as to know any thing of the face of the country; nor much indulged myself in geological enquiries, from a belief that the skin-deep scratches which we can make or find on the surface of the earth do not repay our time with as certain & useful deductions as our pursuits in some other branches. the subject of our winds is more familiar to me. on that the views you have taken are always great, supported in their outlines by your facts; and though more extensive observations, and longer continued may produce some anomalies, yet they will probably take their place in this first great canvas which you have sketched. in no case perhaps does habit attach our choice or judgment more than in climate. the Canadian glows with delight in his sleigh & snow, the very idea of which gives me the shivers. the comparison of climate between Europe & N. America, taking together it’s corresponding parts, hangs chiefly on three great points. 1. the changes between heat and cold in America are greater & more frequent, & the extremes comprehend a greater scale on the thermometer in America than in Europe. habit however prevents these from affecting us more than the smaller changes of Europe affect the European. but he is greatly affected by ours. 2. our sky is always clear; that of Europe always cloudy. hence a greater accumulation of heat here than there, in the same parallel. 3. the changes between wet and dry are much more frequent and sudden in Europe than in America. though we have double the rain, it falls in half the time. taking all these together I prefer much the climate of the United states to that of Europe. I think it a more chearful one. it is our cloudless sky which has eradicated from our constitutions all disposition to hang ourselves, which we might otherwise have inherited from our English ancestors. during a residence of between 6. and 7. years in Paris, I never, but once, saw the sun shine through a whole day, without being obscured by a cloud in any part of it: and I never saw the moment, in which, viewing the sky through it’s whole hemisphere, I could say there was not the smallest speck of a cloud in it. I arrived at Monticello, on my return from France, in January, & during only two months stay there, I observed to my daughters, who had been with me to France, that twenty odd times, within that term, there was not a speck of a cloud in the whole hemisphere. still I do not wonder that an European should prefer his grey, to our azure sky. habit decides our taste in this as in most other cases.

The account you give of the yellow fever, is entirely agreeable to what we then knew of it. further experience has developed more & more it’s peculiar character. facts appear to have established that it is originated here by a local atmosphere, which is never generated but in the lower, closer & dirtier parts of our large cities, in the neighborhood of the water: and that, to catch the disease, you must enter the local atmosphere. persons having taken the disease in the infected quarter, & going into the country, are nursed & buried by their friends, without an example of communicating it. a vessel going from the infected quarter, and carrying it’s atmosphere in it’s hold into another state, has given the disease to every person who there entered her. these have died in the arms of their family without a single communication of the disease. it is certainly therefore an epidemic, not a contagious disease; and calls on the chemists for some mode of purifying the vessel by a decomposition of it’s atmosphere, if ventilation be found insufficient. in the long scale of bilious fevers, graduated by many shades, this is probably the last & most mortal term. it siezes the native of the place equally with strangers. it has not been long known in any part of the US. the shade next above it, called the stranger’s fever has been coeval with the settlement of the larger cities in the Southern parts, to wit, Norfolk, Charleston, New Orleans. strangers going to these places in the months of July, August or September, find this fever as mortal as the genuine yellow fever. but it rarely attacks those who have resided in them some time. since we have known that kind of yellow fever which is no respecter of persons, it’s name has been extended to the stranger’s fever, and every species of bilious fever which produces a black vomit, that is to say a discharge of very dark bile. hence we hear of yellow fever on the Allegany mountains, in Kentucky &c. this is a matter of definition only: but it leads into error those who do not know how loosely, & how interestedly some physicians think & speak. so far as we have yet seen, I think we are correct in saying that the Yellow fever which siezes on all indiscriminately, is an ultimate degree of bilious fever never known in the US. till lately, nor farther South, as yet, than Alexandria: and that what they have recently called yellow fever in New Orleans, Charleston & Norfolk, is what has always been known in those places as confined chiefly to strangers, & nearly as mortal to them, as the other is to all it’s subjects. but both grades are local: the strangers fever less so, as it sometimes extends a little into the neighborhood; but the yellow fever rigorously so, confined within narrow & well defined limits, & not communicable out of those limits. such a constitution of atmosphere being requisite to originate this disease as is generated only in low close, and ill-cleansed parts of a town, I have supposed it practicable to prevent it’s generation by building our cities on a more open plan. take for instance the chequer board for a plan. let the black squares only be building squares, and the white ones be left open, in turf & trees. every square of houses will be surrounded by four open squares, & every house will front an open square. the atmosphere of such a town would be like that of the country, insusceptible of the miasmata which produce yellow fever. I have accordingly proposed that the enlargements of the city of New Orleans, which must immediately take place, shall be on this plan. but it is only in case of enlargements to be made, or of cities to be built that this means of prevention can be employed.

The genus irritabile vatum could not let the author of the Ruins publish a new work, without seeking in it the means of discrediting that puzzling composition. some one of these holy calumniators has selected from your new work every scrap of a sentence, which, detached from it’s context, could displease an American reader. A Cento has been made of these which has run thro’ a particular description of newspapers, and excited a disapprobation even in friendly minds, which nothing but the reading of the book will cure. but time and truth will at length correct error.

Our countrymen are so much occupied in the busy scenes of life that they have little time to write or invent. a good invention here therefore is such a rarity as is lawful to offer to the acceptance of a friend. a mr Hawkins of Frankford near Philadelphia has invented a machine which he calls a Polygraph, and which carries 2. 3. or 4. pens. that of 2. pens, with which I am now writing, is best; and is so perfect that I have laid aside the copying-press for a twelvemonth past, & write always with the Polygraph. I have directed one to be made of which I ask your acceptance. by what conveyance I shall send it while Havre is blockaded, I do not yet know. I think you will be pleased with it, & will use it habitually as I do; because it requires only that degree of mechanical attention which I know you to possess. I am glad to hear that M. Cabanis is engaged in writing on the reformation of medecine. it needs the hand of a reformer, and cannot be in better hands than his. will you permit my respects to him and the Abbé de la Roche to find a place here.

A word now on our political state. the two parties which prevailed with so much violence when you were here are almost wholly melted into one. at the late Presidential election I have recieved 162. votes against 14. only. Connecticut is still federal by a small majority: and Delaware on a poise as she has been since 1775. and will be till Anglomany with her yields to Americanism. Connecticut will be with us in a short time. tho’ the people in mass have joined us, their leaders had committed themselves too far to retract. pride keeps them hostile, they brood over their angry passions and give them vent in the newspapers which they maintain. they still make as much noise as if they were the whole nation. unfortunately these being the mercantile papers, published chiefly in the seaports, are the only ones which find their way to Europe, & make very false impressions there. I am happy to hear that the late derangement of your health is going off, and that you are re-established. I sincerely pray for the continuance of that blessing, and with my affectionate salutations, tender you assurances of great respect & attachment.