the supply of rivers, and the economy of vegetation. Now, to compare this with the quantity of water discharged by all the known rivers of the world, we shall take, with Buffon, the example of the Po. This river, according to Riccioli, before it divides into branches, has a mean breadth of 1000 feet, and a depth of ten feet, with a velocity of four miles per hour. Consequently, it conveys into the sea about 5,000,000,000 cubic feet per day, or nearly 2,000,000,000,000 cubic feet annually; so that, if we suppose a fifth part of the water which descends in rain upon the land to be dissipated again by evaporation, and another fifth to be decomposed by the processes of vegetation, we should still have remaining as much water as would supply 1500 rivers equal in size to the Po.

Or if we take this view of the subject; the Po appears to traverse a country about 380 miles in length, and the rivers which flow into it on each side arise from sources which are about sixty miles distant from the main stream. Thus the Po, and the rivers which

it receives, water a country of about 45,600 square miles. But the surface of the dry land being, according to Buffon's estimate, 63,728,938 square miles, (Buffon's Nat. Hist. i. 136;) if we suppose that each portion of the earth's surface, equal in extent to the basin of the Po, is furnished with a river of the same magnitude, we should have by this computation about 1400 rivers of the same size with the Po to drain the surface of the globe.

It appears by some late experiments of M. Escher, that the annual discharge of the Rhine at Basle is 1,046,763,676,000 cubic feet; that of the Tay appears, from observations made at Perth by the writer of this article, to be about 100,000,000,000 cubic feet, being only about a tenth part of the quantity of water conveyed by the Rhine. The basin of the Tay is 2315 square miles, and the annual supply of rain which it receives about 130,000,000,000 cubic feet; so that, for that extent, about 30,000,000,000 cubic feet of water return to the atmosphere by evaporation or decomposition. In July, 1819, after a long drought, the discharge of the Tay was found to be reduced to 457 cubic feet per second, being only about a tenth part of the average quantity which it conveys to the sea.

cipitous, since, in sounding, the water suddenly deepens from 20 and 30 to 200 fathoms. In this place, as well as in others, where this kind of fishery is carried on, it is found that the best fishing exists at the greatest depths; nor is it unusual to sink the long lines in water of 250 fathoms deep. But the time required for setting and drawing up from this depth, the enormous length of line that is used is so great, as to prevent the fishermen from making any attempts in deeper water; but they are all of opinion that this fish abounds most in the deepest places, and might advantageously be fished for at much greater depths. Thus the ling, for one, is proved to reside in places which must be perpetually dark, although we were to double M. Bouguer's estimate of the point of non-transmission.

It is perfectly known to fishermen that many species, which, in summer, frequent the shallow seas, apparently for the purpose of spawning chiefly, retire to the great depths in winter; and, as these persons suppose, to avoid the cold. The regions of darkness seem to be their proper residence; while, like the salmon and other migratory fishes, they are merely visitors in those of light. But, besides this, a very large proportion of all the fishes of the sea only preys by night, while there are some that do so by day, and others are ready for their food at all times. In the polar regions, and in the depths of winter, there can for a long period be no light in the sea, whatever faint glimmering the atmosphere, the planets, or the aurora, may yield for the inhabitants of the land. Yet here many fishes, and most conspicuously, some of the whales and the swordfish have their perpetual residence. These animals can have no light for a long time, particularly in their deep waters, unless they find it in their own bodies, or in that of their prey. The food of the great whale, consisting of various insects and worms, very commonly shrimps, such as the Cancer oculatus, resides at the bottom as well as on the top of the sea; and there cannot, therefore, be any doubt that, even in summer, but most assuredly in winter, it feeds in regions that are inaccessible to light.

The quantity of water discharged by rivers into the sea has been imperfectly examined. From facts, which we have already stated, the mean annual quantity of rain over the globe may be estimated about three feet; which would give no less than 16,000,000,000,000,000 cubic feet for the quantity of rain over the whole surface. If we suppose that a third part of this falls upon the land, we should have upwards of 5,000,000,000,000,000 cubic feet for

the supply of rivers, and the economy of vegetation. Now, to compare this with the quantity of water discharged by all the known rivers of the world, we shall take, with Buffon, the example of the Po. This river, according to Riccioli, before it divides into branches, has a mean breadth of 1000 feet, and depth of ten feet, with a velocity of four miles per hour. Consequently, it conveys into the sea about 5,000,000,000 cubic feet per day, or nearly 2,000,000,000,000 cubic feet annually; so that, if we suppose a fifth part of the water which descends in rain upon the land to be dissipated again by evaporation, and another fifth to be decomposed by the processes of vegetation, we should still have remaining as much water as would supply 1500 rivers equal in size to the Po.

Or if we take this view of the subject; the Po appears to traverse a country about 380 miles in length, and the rivers which flow into it on each side arise from sources which are about sixty miles distant from the main stream. Thus the Po, and the rivers which

it receives, water a country of about 45,600 square miles. But the surface of the dry land being, according to Buffon's estimate, 63,728,938 square miles, (Buffon's Nat. Hist. i. 136;) if we suppose that each portion of the earth's surface, equal in extent to the basin of the Po, is furnished with a river of the same magnitude, we should have by this computation about 1400 rivers of the same size with the Po to drain the surface of the globe.

It appears by some late experiments of M. Escher, that the annual discharge of the Rhine at Basle is 1,046,763,676,000 cubic feet; that of the Tay appears, from observations made at Perth by the writer of this article, to be about 100,000,000,000 cubic feet, being only about a tenth part of the quantity of water conveyed by the Rhine. The basin of the Tay is 2315 square miles, and the annual supply of rain which it receives about 130,000,000,000 cubic feet; so that, for that extent, about 30,000,000,000 cubic feet of water return to the atmosphere by evaporation or decomposition. In July, 1819, after a long drought, the discharge of the Tay was found to be reduced to 457 cubic feet per second, being only about a tenth part of the average quantity which it conveys to the sea.

PESTILENCE IN PHILADELPHIA.

The following notice of the malignant fever which desolated this city in 1793 is extracted from a pamphlet written by the well known citizen, Matthew Carey :

"MOST people who could by any means make it convenient, fled from the city. Of those who remained, many shut themselves up in their houses, and were afraid to walk the streets. The smoke of tobacco being regarded as a preventive, many persons, even women and small boys, had segars constantly in their mouths. Others placing full confidence in garlic, chewed it almost the whole day; some kept it in their shoes. Many were afraid to allow the barbers or hair dressers to come near them, as instances had occurred of some of them having shaved the dead, and many of them had engaged as bleeders. Some who carried their caution pretty far, bought lancets for themselves, not daring to be bled with the lancets of the bleeders. Some houses were hardly a moment in the day free from the smell of gunpowder, burned tobacco, nitre, sprinkled vinegar, &c. Many of the churches were almost deserted, and some wholly closed. The coffee house was shut up, as was the city library, and most of the public offices; three out of the four daily papers were dropped, as were some of the other papers. Many were almost incessantly purifying, scouring and whitewashing their rooms. Those who ventured abroad, had handkerchiefs or sponges impregnated with vinegar or camphor at their noses, or else smelling bottles with the thieves' vinegar. Others carried pieces of tarred rope in their hands or pockets, or camphor bags tied round their necks. The corpses of the most respectable citizens, even those who did not die of the epidemic, were carried to the grave on the shafts of a chair, the horse driven by a negro, unattended by a friend or relation, and without any sort of ceremony. People hastily shifted their course at the sight of a hearse coming towards them. Many never walked on the foot path, but went into the middle of the streets, to avoid being infected in passing by houses wherein people had died. Acquaintances and friends avoided each other in the streets, and only signified their regard by a cold nod. The old custom of shaking hands fell into such general disuse, that many were affronted even at the offer of the hand. person with a crape or any appearance of mourning, was shunned like a viper. And many valued themselves highly on the skill and address with which they got to windward of every person they met. Indeed it is not probable that London, at the last stage of the

A

plague, exhibited stronger marks of terror than were to be seen in Philadelphia, from the 25th or 26th of August till pretty late in September. When people summoned up resolution to walk abroad and take the air, the sick cart conveying patients to the hospital, or the hearse carrying the dead to the grave, which were travelling almost the whole day, soon damped their spirits, and plunged them again into despondency.

"With the poor the case was, as might be expected, infinitely worse than with the rich. Many of these have perished, without a human being to hand them a drink of water, to administer medicines, or to perform any charitable office for them. Various instances have occurred, of dead bodies found lying in the streets, of persons who had no house or habitation, and could procure no shelter.

"A man and his wife, once in affluent circumstances, were found lying dead in bed, and between them was their child, a little infant, who was sucking its mother's breast. How long they had lain thus was uncertain.

"A woman, whose husband had just died of a fever, was seized with the pains of labor, and had nobody to assist her, as the women in the neighborhood were afraid to go into the house. She lay for a considerable time in a degree of anguish that will not bear description; at length she struggled to reach the window, and cried out for assistance; two men, passing by, went up stairs, but they came at too late a stage; she was striving with death, and actually in a few minutes expired in their arms.

"Another woman, whose husband and two children lay dead in the room with her, was in the same situation as the former, without a midwife, or any other person to aid her. Her cries at the window brought up one of the carters employed by the committee for the relief of the sick. With his assistance she was delivered of a child, which died in a few minutes, as did the mother, who was utterly exhausted by her labor, by the disorder, and by the dreadful spectacle before her. And thus lay in one room no less than five dead bodies, an entire family, carried off in an hour or

two.