There is no doubt, that it is a duty incumbent on us by all laws, human and divine; and whenever the magistrates shall enjoin this work, it will be the duty of christian ministers to inculcate the punctual performance of it on their hearers, that men's consciences may be awakened by the heinousness of the sin, as the neglect of so necessary a duty certainly is the nourishment of this destructive leaven. In the last place, it is necessary to observe, that the summer is no proper season for cleansing the city from corrupting filth, for the stirring it at that time increases the quantity of vapours, and the doing it at that time has been observed to produce the most direful havoc among the inhabitants. The most proper season is, toward the end of winter, when the fermentation is entirely destroyed, and the doing it at that season will have another advantage, that less filth collected in the winter will remain on the approach of summer.

P.S. I forgot to mention a remarkable confirmation, in sight of the town, of what has been advanced in the preceding treatise. A fresh water pond and meadow of stagnating water, not half a mile to the northward of the city of New-York, has been lately drained for the benefit of the soil, without any thought of any advantage to the health of the neighbouring inhabitants, though its effects in that respect be very manifest. Every summer the inhabitants of the houses on the north side of it, before it was drained, were subject to malignant intermittents, and several, in the few houses there, yearly died. Since the draining of that place, these houses are become as healthy as any in the neighbourhood. Caspar Cantarini, in his account of the republic of Venice, mentions a new college, or council of magistrates, appointed not long before his time,

Tt

to take care of the health of that city, and whose business, among other things, was to cause all filth and every nuisance to be removed, and the city kept clean. He observes that, before this institution, Venice had been frequently subject to pestilential distempers, insomuch, that many of the inhabitants for that reason had deserted their houses, and removed their families to the continent, but, that after these magistrates were appointed, who continued vigilant in their duty, the city had always remained free from any grievous pestilential distempers, though there had been several instances of such like distempers breaking out from time to time in private houses and quarters, which, by the care of this magistracy, had been always kept from spreading or becoming epidemical.

IV.

OBSERVATIONS on the FALLS of the OHIO, by Col. JoNATHAN WILLIAMS, President of the United States' Military Philosophical Society, Fellow of the American Philosophical Society, &c. &c.*

(Read October 5th, 1806.).

To the Chairman of the United States' Military Philosophical

SIR,

Society.

West-Point, October 4th, 1806.

I HAVE more than once heard it observed, that it is the duty of every man, to make the natural history of his

* In conformity to a vote of the United States' Military Philosophical Society, the Editors have been favoured with a copy of the following valuable communications (the 4th and 5th articles) made to that body, by their learnedPresident. EDITORS.

own country as much known as possible, and, if his knowledge were but a mite, he is bound to throw it into the common stock; thereby to improve and extend the benefits which Providence has bestowed on this favoured part of the world.

Impressed with this sentiment, I am induced to send you my mite, which if it cannot rise to the title of a benefit, may at least gratify curiosity.

The river Ohio, which, on account of its peculiar beauty, was emphatically called "La Belle Rivière," by the French, has but one bed of rocks, that runs across it, throughout its whole course, from Pittsburg to the Mississippi. This obstruction is at Louisville, and, although the rapids occasioned by it, are called Falls, they are not such, as absolutely prevent navigation: but they are sufficient to render it both difficult and dangerous. My examination of these falls, being incidental to my passage down the river, and confined within the limits of a traveller's time, a full and minute description cannot be expected; but, in order to convey, as accurately as possible, all that was discovered, I shall adopt the style of narrative, and mention every cir

cumstance.

In the month of August, 1801, I descended the Ohio, with troops and stores under my command, in large boats, and arrived at Louisville, when the waters were at the lowest, and but one of the shoots,* as they are called, could be navigated.

* Probably a corruption of the French, chute, or fall.

Mr. Nelson, of Louisville, who was engaged to pilot the boats through, observed to me, in the course of conversation, that there were a great many curious petrifactions on the rocks in these Falls, particularly of the excrements of geese, and of buffaloes' horns. This account appeared to me fabulous, for it was inconceivable that light substances could be retained an instant, in a rapid current, far less was it possible to believe, that they could become petrified in that spot alone, and not in other parts, where the water, being in a more quiet state, is better able to exercise its petrifying quality on substances at rest in it.

The next day, I went with Mr. Nelson to the edge of the farthest shoot, passing over two, one of which was almost dry, and the other about knee deep. The whole space, between the second and third shoot, was strewed with these appearances, which much resembled what they were supposed to be, as to external form, but various in size. On breaking one of them, there appeared to be a regular arrangement of longitudinal fibres; and, upon my remarking to Mr. Nelson, that although this might be the case in a horn, it was absolutely impossible in excrementitious matter, he noticed its resemblance to a root, and it instantly occurred to me, that if these appearances had been roots, I should, by tracing their origin from the smaller towards the larger ends, as they appeared here and there above the surface, arrive at the tree from which they issued: the search soon brought me to the complete form of a stump, apparently cut off horizontally, and I could trace its annulars and radii, as accurately as I could have done in a sawed log of wood. The surface was as smooth as a hone, and so hard that I could not break off any part with an axe, but fairly beat the head of it into a

shapeless mass, by repeated blows. The utmost I could obtain was a few small pieces, where they happened to be detached and project a little from the mass, which appeared to be one bed of petrifaction.

On a farther examination, I found many more trees, and could distinguish various kinds; some were of a fine red colour in the centre, diminishing to white at the circumference, and plainly appeared to have been red cedar : others were very compact, and of a light straw colour, like the beech: others of a darker colour, more separated fibres, and more distant annulars, like the oak; some we found in an inclined posture, so that the section being oblique, made the annulars appear eliptical; others were nearly horizontal, like fallen trees, and displayed the appearance of a well planed board, somewhat across the grain. Upon further examination, it appeared evident to us, that the whole mass of rock had been a forest of large trees, and the surface we saw, might be easily conceived, by imagining a number of trees to be very smoothly cut level with the hard ground, and every species of vegetation to be swept away, while the superficial roots protrude about half of their diameter, in many places, and then dip under ground again. Our parade at the cantonment, near the mouth of the Ohio, having been made out of a forest, exhibited precisely the same appearance, except the distinction of wood and earth in one, and a petrified mass in the other. Whoever will give themselves the trouble of examining the superficial and repent roots of our lombardy poplars, will see, in part, an exemplification of what I mean to describe.

After establishing these facts, the next thing should be,