ground, watered with a small rivulet, that it may be easily overflowed, which they do by making dams across it: they make these dams by thrusting down stakes of five or six feet long, and as thick as one's arm, pretty deep into the ground; these they will wattle across with tender pliable boughs, and fill up the spaces with clay, making a slope on the side against which the water presses, but leaving the other perpendicular. They make their houses after the same manner; the walls are upright, two feet thick, and at top in form of a dome; they are usually oval, five or six feet long on the inside, and near as broad, being sufficient to lodge eight or 10 beavers, and two or three stories high, which they inhabit as the water rises or falls.

Sometimes they build several houses near together, which communicate with one another. He says there are some beavers called terriers, which burrow in the earth: they begin their hole at such a depth under water as they know that the water will not freeze so deep; this they carry on for five or six feet, and but just large enough for them to creep through; then they make a bathing-place three or four feet every way; from whence they continue the burrow, always ascending by stories, that they may lodge dry as the waters rise some of these burrows have been found to be 100 feet long. They cover the places where they lie with weeds; and in winter they make chips of wood, which serve them for mattresses: they live on herbs, fruits, and roots in summer; but against winter they lay up a provision of wood: a stack of 25 or 30 feet square, and eight or ten high, is the usual quantity for eight or ten beavers; they only eat those pieces which are soaked in the water.

A female beaver was kept at Sir Hans Sloane's, in his garden, for about three months. She was but about half grown, not being above 22 inches long from the nose to the root of the tail; the tail eight inches long. She was very thick, paunch-bellied; the shape of the head, and indeed of the whole animal, except the tail, and hind feet, very much resembled a great over-grown water-rat.

Her food was bread and water; some willow-boughs were given her, of which she ate but little; but when she was loose in the garden, she seemed to like the vines much, having gnawed several of them from as high as she could reach quite down to the roots: she gnawed the jessamine likewise, but least of all some holly trees. When she ate, she always sat on her hind legs, and held the bread in her paws like a squirrel. When she slept, she commonly lay on her belly, with her tail

under her. In swimming, she held her fore-feet close up under her throat, and the claws closed, as when one brings the ends of one's thumb and of all the fingers close together, never moving her fore feet till she came to the shore, and endeavoured to get out. She swam with her hind feet only, which had five toes, and were webbed like those of a goose; the tail, which was scaly, and in form of the blade of an oar, served as a rudder, with which she steered herself, especially when she swam under water, which she would do for two or three minutes, and then come up to breathe; sometimes raising her nostrils only above water: she swam much swifter than any water-fowl, moving under water as swift as a carp. The hind legs being much longer than the fore, made her walk but slowly, or rather waddle like a duck, when on dry land; and if driven along fast, she could not run, but went by jumps, flapping her tail against the ground. Her excrements were always black, and very fetid; her urine turbid and whitish, and very strong scented. She made no noise, except a little kind of grunting, when driven fast and angred. She seemed very brisk, and thrived well with the above-mentioned food, being turned into the fountain to bathe three or four times a week. She had one day convulsion fits, very like the epilepsy in men, from which she recovered soon, and was very well after them, till at last she was killed by a dog.

On the Cause of the General Trade Winds. By GEORGE HADLEY, Esq. F.R. S.—[1735.]

THAT the action of the sun is the original cause of these winds, it seems all are agreed; and that it effects them by causing a greater rarefaction of the air in those parts on which its rays, falling nearly perpendicular, produce a greater degree of heat there than in other places; by which means the air becoming specifically lighter than the rest round about, the cooler air will, by its greater density and gravity, remove it out of its place, and make it rise upwards. But it seems that this rarefaction will have no other effect than to cause the air to rush in from all parts, into the place where it is most rarefied, especially from the north and south, where the air is coolest, and not more from the east than the west, as is commonly supposed. So that, setting aside the diurnal motion of the earth, the tendency of the air would be from every side towards that part where the sun's action is most intense at the time, and so a north-west wind be produced in the morning, and a north-east in the afternoon, by turns, on this

side of the parallel of the sun's declination, and a south-west and south-east on the other side.

That the perpetual motion of the air towards the west cannot be derived merely from the action of the sun upon it, appears more evidently from this: if the earth be supposed at rest, that motion of the air will be communicated to the superficial parts, and by little and little produce a revolution of the whole the same way, except there be the same quantity of motion given the air in à contrary direction in other parts at the same time; which is hard to suppose. But if the globe of the earth had before a rotation towards the east, this by the same means must be continually retarded: and if this motion of the air be supposed to arise from any action of its parts on each other, the consequence will be the same. For this reason it seems necessary to show how these phenomena of the trade winds may be caused, without producing any real general motion of the air westwards. This will readily be done by taking in the consideration of the diurnal motion of the earth: for, let us suppose the air in every part to keep an equal pace with the earth in its diurnal motion; in which case there will be no relative motion of the surface of the earth and air, and consequently no wind; then by the action of the sun on the parts about the equator, and the rarefaction of the air thence proceeding, let the air be drawn down thither from the north and south parts.

The parallels continually enlarge, as they approach to the equator, and the equator exceeds the tropics nearly in the ratio of 1000 to 917; consequently their difference in circuit is about 2083 miles, and the surface of the earth at the equator moves so much faster than the surface of the earth with its air at the tropics. From which it follows, that the air, as it moves from the tropics towards the equator, having a less velocity than the parts of the earth it arrives at, will have a relative motion contrary to that of the diurnal motion of the earth in those parts; which being combined with the motion towards the equator, a north-east wind will be produced on this side of the equator, and a south-east on the other side. These, as the air comes nearer the equator, will become stronger, and more and more easterly, and be due east at the equator itself, according to experience, by reason of the concourse of both currents from the north and south, where its velocity will be at the rate of 2083 miles in the space of one rotation of the earth or natural day, and above one mile and a third in a minute of time; which is greater than the velocity of the wind is supposed to be in the greatest storm, which, accord

ing to Dr. Derham's observations, is not above one mile in a minute. But it is to be considered, that before the air from the tropics can arrive at the equator, it must have gained some motion eastward from the surface of the earth or sea; by which its relative motion will be diminished; and in several successive circulations may be supposed to be reduced to the strength it is found to be of.

Account of the Experiments made June 1. 1734, before several Members of the Royal Society, and others, on a Man, who suffered himself to be bitten by a Viper, or common Adder; and on other Animals likewise bitten by the same, and other Vipers. By CROMWELL MORTIMER, M. D. Seer. R.S.

WILLIAM OLIVER and his wife, from Bath, who follow the business of catching and selling vipers, offered themselves to be bitten by any viper that should be procured, trusting to the virtue of a remedy they had discovered, in trying a variety of things, when the woman was once accidentally bitten, and the usual known medicines, even the oil of vipers, had no effect in assuaging her pains, especially of her breast on the same side as the hand in which she had received the wound. This remedy, which is only common oil of olives, and, from its use with salad, is commonly known by the name of salad oil, recommends itself not only for its efficacy, but also on account of its being readily attainable when accidents happen.

On the 1st of June, 1734, in the presence of a great number of persons, the said William Oliver was bitten by an old black viper, or adder, brought by one of the company, on the wrist and joint of the thumb of the right hand, so that drops of blood came from the wounds. He said that he immediately felt a violent pain and shooting from the wounds, both to the top of his thumb and up his arm, even before the viper was loosened from his hand; soon after he felt a pain, resembling that of burning, trickle up his arm; in a few minutes his eyes began to look red and fiery, and to water much in less than half an hour, he perceived the venom seize his heart, with a pricking pain, which was attended with faintness and shortness of breath; on which he fell into violent cold sweats: in a few minutes after this, his belly began to swell, with great gripings and pains in his back, which were attended with violent vomitings and purgings. He said, that during the violence of these symptoms, his sight was gone twice, for several minutes at a time, but that he could hear all the while. He stated, that in his former ex

periments he had never deferred making use of his remedy longer than when he perceived the effects of the venom reaching his heart; but this time, being willing to satisfy the company thoroughly, and trusting to the speedy effects of the oil, which had never failed him, when used in time, he forbore to apply any thing till he found himself exceedingly ill, and quite giddy.

About an hour and a quarter after he had been first bitten, a chafing-dish of glowing charcoal was brought in, and his arm, the clothes being stripped off, was held over it, as near as he could bear it, while his wife rubbed in with her hand the salad oil (which Dr. M. had procured and kept himself in his pocket, lest they should privately add any thing to it, having bought it by the name of Lucca oil). Turning his arm continually round, as if she would have roasted it over the coals; he said that the pain soon abated, but the swelling did not diminish much: most violent vomitings and purgings soon ensued, and his pulse became low and often interrupted a glass or two of olive oil drank down, seemed to give him some ease.

Continuing in this dangerous condition, he was put to bed, as soon as one could be got ready for him, where his arm was again bathed with his remedy over a pan of charcoal set by the bed-side; but continuing to complain much of his back and belly, Dr. M. advised his wife to rub them likewise with salad-oil, heated in a ladle over the charcoal: which she did accordingly; on which he declared he found immediate ease, as if by some charm; and he had not above two or three retchings to vomit and stools afterwards, but made water plentifully, which was not discoloured. He then soon fell into a sound sleep, but was often interrupted by persons coming to see and enquire after him, till near 12 o'clock, from which time he slept continually to five or six next morning, when he awaked and found himself very well; but in the afternoon, on drinking some rum and strong beer, so as to be almost inebriated, the swelling returned with much pain, and cold sweats; which abated soon, on bathing the arm as before, and wrapping it up in brown paper soaked with oil.

June 3. the man's arm remained swelled, looked red, marbled with spots of yellow, but felt soft; and he had the perfect use of it, and even of his fingers, no pain or stiffness being left. He then caused a small spaniel dog to be bitten on the nose by a fresh viper: some oil was immediately applied hot, and rubbed well in, till all the hair of his nose was