its former fluidity. Mr. Epinus went further in order to examine the quicksilver when it was made solid. He poured quicksilver into a glass tube as thick as one's finger, closed at bottom, but open at top. The quicksilver in this cylinder, which was about one inch and a half long, froze in three quarters of a minute; and he observed that it became solid, perfectly resembling other metals, except iron: it continually contracted, and its surface, which was at first pretty high, soon sunk very low. This cylinder of frozen quicksilver sunk to the bottom of fluid quicksilver, in the same manner as is observed of other metals except iron. We know the contrary happens with regard to water frozen and other fluids, which extend as they become solid, and their ice swims in the fluid matter of which they were produced.

for

Dec. 26. in the morning, between nine and ten, the cold became extremely sharp at 211°, and such as exceeded the greatest degree of artificial cold fixed by Fahrenheit; 40° below zero, in Fahrenheit's thermometer, is equal to 210° of that of De Lisle.

Mr. Braun repeated this experiment again exactly with the same success with that of the day before. The Counsellor and Professor Lomonossow made the same experiment on the same day; and by means of aquafortis the cold came to 495 degrees. He then poured in spirit of common or sea salt, and the quicksilver fell down in the thermometer to 554 degrees; and in taking the thermometer from the mixture the quicksilver continued to fall in the open air to the 552d degree. He threw yet into the glass a little more snow, pouring on it some oil of vitriol, and suddenly the quicksilver fell to 1260 degrees. He then broke the ball, and found the mercury changed to a solid body. The quicksilver, which yet remained in the tube, was also become solid, and appeared like a loose silver wire attached to the ball, which was flexible every way. He gave the ball of quicksilver several blows with a turned axe, and it became flat like a half ruble, or English half crown; but receiving thereby some cracks, it dissolved in about 20 minutes. These experiments were made when the air was at about 208 degrees of cold.

Of a Whirlwind in New England. By Mr. JOHN WINTHROP, Prof. of Phil. at Cambridge, U.S. — [1761.]

THE morning of July 10. was fair and hot, with a brisk gale at south-west. At Leicester, 40 miles westward, about five o'clock the sky looked strangely; clouds from the south-west

and north-west seemed to rush together very swiftly, and im mediately on their meeting commenced a circular motion; presently after which a terrible noise was heard.. The whirlwind passed along from south-west to north-west. Its first effects were discernible on a hill, where several trees were thrown down at considerable distances from each other. In this manner it proceeded the distance of six miles with the most destructive violence, tearing up and scattering about the trees, stones, fences, and every thing else in its way, forming a continued lane of ruins, of a few rods wide.

It met with only one dwelling-house in its course, that of one David Lynde, on which it fell with the utmost fury, and in a moment effected its complete destruction. The house was of wood, two stories high, and both the chimnies of stone. Near the house were a shop and small shed; and the barn stood on the opposite side of the road, about 10 rods distant. As soon as they perceived the storm coming near the house some men within endeavoured to shut the south door; but before they could effect it they were suprised by the falling of stones around them, from the top of that chimney which was in the middle of the house. All the people in the house were in that instant thrown into such a consternation, that they can give no account of what passed during this scene of confusion, which was indeed very short. Where the house stood nothing remained but the sills, and the greater part of the lower floor, with part of the two stacks of chimnies, one about 10 feet, and the other not quite so high; the stones which had composed the upper part lying all around them. Except these sills, there were only three pieces of timber, and those very large, left entire; one of which, about 16 feet long, and 10 inches by eight, was found on the opposite side of the road, nearly south, about 20 rods distant from the house. The rest of the timbers, from the greatest to the least, lay broken and twisted to pieces between N. N. E. and E. for 70 or 80 rods from the house; some on the ground, others sticking into it a foot and two feet deep in all directions. Part of one of the main posts, about 10 feet long, with part of one of the plats of nearly the same length, and a brace which holds them together, were left sticking in the ground, nearly perpendicular, to a great depth, in a field southerly from the house about eight rods distant. The boards and shingles of the house, with 3000 or 4000 new boards which lay by it, were so entirely shattered, that scarcely a piece could be found above four or five inches wide, and vast numbers were not more than two fingers wide; some within the course of the wind and some without, at

great distances on both sides of it. What has been said of the boards and shingles was likewise true of the wooden furniture of the house: the tables, chairs, desks, &c. shared the same fate; not a whole stick was to be found of any of them. Some of the beds that were found were hanging on high trees at a distance. Of the heavy utensils, pewter, kettles, and iron pots, scarcely any were found. Some nails that were in a cask in the east chamber were driven in great numbers into the trees on the eastern side of the house. The shop and shed before mentioned were torn in pieces, nothing of the shop remaining but the sills and floor; and a horse standing under the shed was killed. Only one person was killed.

From the whole, it seems highly probable that the house was suddenly plucked off from the sills (to which the upright posts are not fastened), and taken up into the air, not only above the heads of the persons who were on the lower floor, but to the height of those parts of the chimnies which were left standing, where, by the violent circular motion of the air, it was immediately hurled into ten thousand pieces, and scattered to great distances on all quarters, except that from which the wind proceeded. And it further appears, that the violence of the wind in that place was over as soon as the house was taken up.

Burning Cliffs in Dorsetshire. By JOHN STEPHENS, M.A.

IN August, 1751, the air, having been for some time remarkably hot and dry, was changed suddenly by a heavy fall of rain, and a high south-west wind. The cliffs near Charmouth, in the western part of Dorsetshire, presently after this alteration of the atmosphere, began to smoke, and soon after they burned, with a visible though a subtle flame for several days successively; and continued to smoke, and sometimes to burn at intervals, till the approach of winter: nay, ever since that time, especially after any great fall of rain, thunder, and lightning, or a high south-west wind, (which drives the sea with great violence against the cliffs, and beats off large pieces of them,) the cliffs continue to smoke, and sometimes to burn with a visible flame; which during the summer-months is frequently observed in the night-time. On examining these cliffs, in the year 1759, Mr. S. discovered" a great quantity of pyrites, not in any regular strata, but interspersed in large masses through the earth, and which proved to be martial; of marcasites, which yielded near one tenth part of common sulphur; of cornua ammonis of dif

ferent sizes, and other shells, but of the bivalve class, which were crusted over, and as it were mineralised with the pyritical matter; of belemnites, also crusted over with the like substance: and the cliffs, for near two miles long, and from the surface, to 35 or 40 feet deep, even to the rocks at high water-mark, were one bed of a dark-coloured loam, strongly charged with bitumen. He found also a darkcoloured substance, resembling coal-cinder; some of which being powdered, and washed in distilled rain-water, on filtrating the water, and evaporating it slowly to a pellicule, its salts shoot into fine crystals, and appear to be no more than a martial vitriol: one ounce of this cinder-like substance yields one drachm of salt. He gathered up about 100 lb. weight of the different kinds of those pyritæ, marcasites, &c. which were laid in a heap, exposed to the air, and every day sprinkled with water: the consequence was, that in about ten days' time they grew hot, soon after caught fire, burned for several hours, and fell into dust. Hence, therefore, it is imagined that these martial and sulphureous fossils, by being exposed to the air and wet, and by being agitated by the beating of the sea, take fire.

From what has been said Mr. S. draws the following conclusions :-

1. That all subterraneous fires, even those of Hecla, Vesuvius, and Ætna, together with those observed in the mines and coal-pits, are caused by the heat and fixing of pyrites and marcasites. 2. That the waters of our hot baths derive their heat from passing over a bed of ignited pyrites. Indeed the solid contents of those waters do evidently prove this assertion, being nothing more than such particles of the pyrites as are soluble in water. 3. That these mineral flames will be more or less subtle, according to the minuteness of the particles of the combustible matter. 4. That the convulsive motions and tremblings of the earth are caused by the heat of the burning pyrites expanding the air contained in its bowels. This is clearly proved by their causing, immediately after, an eruption of the earth, which generally discharges a dark-coloured, cinder-like, and frothy matter. And, 5. That those places, where the earth contains the greatest quantity of pyrites and marcasites, will be most liable to these convulsive motions and tremblings, no other natural cause contradictory.

On the Extraordinary Agitation of the Waters in Mount's Bay, and other Places, March 31. 1761. By the Rev. W. BORLASE, M. A. F.R.S.— [1762.]

MARCH 31. 1761, about five in the afternoon, there was an uncommon motion of the tide in Mount's Bay, Cornwall. It was full sea that day about half an hour after 12. After the tide had ebbed about four hours and a half, instead of continuing to retreat gradually, as usual, till it had completed the six hours' ebb, on a sudden it advanced as it is usually at the time of the moon, at an hour and a half before high water. It then retreated near to the point of low water, then it advanced again, and retreated, making five advances, and as many recesses in the space of one hour; viz. from about five to six o'clock, which was the whole time that these uncommon stretches of the tide continued. But the first motion was most considerable, the sea advancing the first time to a quarter ebb; whereas the second advance was but as far as the sea reaches at half ebb. At the first surge the waters rose at this place six feet perpendicular.

On the coast of Scotland, from Fort Augustus on Lochness, we had accounts that on the same 31st of March, about two in the afternoon, Lochness rose on a sudden about two feet perpendicularly, and continued alternately rising and falling for the space of three quarters of an hour. The King's galley broke from her moorings, and drove into the loch: several boats were cast very far upon dry land: in the middle of the loch the water swelled up like a mountain, extremely muddy, and the motion was attended with a very uncommon hollow sound.

On the coast of Ireland, from Cork, there was advice that on the same 31st of March, a quarter after noon, a shock of an earthquake was felt in that city, and between the gates only, allowed to be more violent than that of November 1. 1755. It did not continue above one minute, undulating from east to west, and vice versa. At Kinsale, about six o'clock P. M. near dead low water, the tide rose suddenly on the strand, about two feet higher than it was, and went out again in the space of four minutes with great force, which was repeated several times; but the first was the greatest. At Amsterdam the branches in the synagogue were observed to vibrate between one and two o'clock. In the great church at Maesland-Slys, the branches moved about a foot from the perpendicular, and the vessels in the harbour were agitated. But this earthquake was felt more violently on the ocean,