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Gilver unfrozen; but all other fluids take up more space when they are frozen, than before, and their ice fwims on the furface of the fluid matter of which it is the congealation.

greateft poffible degree of cold, than
fpeedy evaporation often repeated
upon the fame fubftance. The fpi-
rit called Ether, is the most vola-
tile now known, and if the bulk of a
thermometer be dipped in this fpi-
rit, and as foon as taken out be
blowed upon with a pair of bellows
till it is dry, then dipped again, and
blowed upon as before, in a quick
and uninterrupted fucceffion, the
quickfilver will be foon frozen. By
the Ruffian experiments, the reports
of travellers of hitherto unfufpected
veracity, are proved to be false; for
they have affirmed, that they found
the mercury frozen in their thermo-
meters when the cold was equal to
200 degrees, but these experiments
concur to prove that it does not be-
come folid till it falls near 300 de-
grees lower. They affirm alfo, that
the thermometer becomes useless,
as foon as the quickfilver is frozen;
but thefe experiments fhew, that,
though folid, it will yet defcend
with a greater degree of cold, for
after it had fallen to 554 degrees,
which
which is 54 beyond the point at
which it freezes, it fell to 1260,
which was 708 degrees lower upon
producing a more intense degree of
cold, by adding more fnow to the
mixture, and pouring oil of vitriol
upon it. It muft, however, be ob-
ferved, that diftilled mercury was
ufed in these experiment, and that
if the quickfilver be adulterated with
lead, it may, perhaps, fooner be-
come folid by cold, than if it is
pure*.

Upon other repetitions of the experiment, when the quickfilver fell to 495 degrees, fome spirit of the fea falt was poured into the mixture of fpirit of nitre and fnow, upon which the quickfilver fell to 554 degrees. Some more fnow being still added, and some oil of vitriol poured upon it, the quickfilver fuddenly funk to 1260 degrees. The ball was then broken, and the mercury found frozen to a folid body, and there is no wonder in that, fince it was frozen to a folid body when the mercury had fallen to 500. But in this experiment, the quicksilver, which still remained in the tube, was become folid, and appeared like a thread of filver wire, flexible every way, and fastened to the ball; the ball they forged into a flat circular form like a half crown, but at length it began to crack, and foon after became again fluid. During this experiment, the natural cold was 208. It is remarkable, that in an experiment made when the natural cold was 183 degrees, the quickfilver being taken out of a mixture in which it had fallen to goo, ftill continued to fall 100 degrees more, though after a certain time it liquified. This phænomenon the Ruffian philofophers have not accounted for; but it will not appear ftrange to those who know that intenfe cold is produced merely by evaporation, and that whatever is once wet, becomes colder as it is growing dry. Nothing more therefore is neceflary to produce the * May we not therefore thus account for what the travellers just spoken of have aðvanced, concerning the mercury freezing fo readily in their thermometers ?

This article has probably undergone two tranflations, one from the Rus into French, and one from the French into English, and accordingly it contains fome obfcurities and inconfiftencies, which we

fhall

Thall beg leave to mention, in hopes of feeing them cleared up in the next volume of that curious and ufeful work from which this account is taken. We are told, that the quickfilver having fallen in the thermometer to 554 degrees, "in taking the thermometer from the mixture the quickfilver continued to fall in the open air, to the 552d degree:" but if 552 is not more than 554, the quickfilver in this cafe did not fall, but rife. We are alfo told that the profeffor, who, by adding fnow and oil of vitriol to the mixture, caufed the mercury to fall from 554 to 1260 deg. is not fure "whether the ball might not have received fome crack, and the quickfilver thereby might have had liberty to fall the lower;" but as the quickfilver is fuppofed to have been frozen to a folid body, not only in the bulb, but the tube, when it was down at 554, it is not eafy to conceive how a crack in the glafs could cause it to defcend 706 degrees more. The directions which are given to enable other philofophers to repeat thefe experiments are not expreffed fo clearly as could be wifhed; we are told it is neceffary to use "fuming fpirit of nitre, or of fuch as is evaporated till the fumes become red, for common aqua fortis will not do." We are then directed to take "this fuming fpirit of nitre, cooled as much as poffible in liquifying fnow, and with it half fill a wine glafs, throwing in as much fnow at the fame time, and ftirring it till it becomes of the confiftence of pap; then you have almoft in an inftant, the neceffary degree for the congealation of quickfilver.'

We are told alfo in one place, that "the greatest part of the ex

periments agree in this, that the quickfilver becomes folid, when it falls in the thermometer 500 deg. more or less;" (i. e.) they agree that there is a certain degree of cold which they do not at all afcertain, that will freeze quickfilver; for the words more or less leave this degree in abfolute uncertainty; and indeed we are told immediately afterwards, that thefe experiments "do not fo fufficiently agree as to deduce any thing certain about it:" It is, however, deduced from the fudden freezing of the quickfilver in a glass tube with artificial cold, "that the cold then produced ought to exceed 300 degrees:" But we are told in the relation of another experiment," that the result of a mixture was an augmentation of cold to 300 degrees, and that it must then happen that the furprifing degree obtained was neceffary to congeal mercury;" from all which it follows, that the degree of cold neceffary to congeal mercury is 500 degrees more or lefs; that it muft exceed 300 degrees, yet that at 300 degrees the furprifing degree is obtained fufficient to congeal mercury.

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blew very cold from the north, and foon after he perceived a kind of rainbow of about 120 degrees extent, the convex part of which was towards the fun, and which feemed to be about the third part of a circle, of which the zenith would have been the center. This bow had all the colours of the iris, the convex part being red, and the concave blue; it faded by degrees, and in about a quarter of an hour wholly difappeared. Soon after M. Nollet obferved in fome white clouds, at equal distances to the right and left of the fun, two ftreaks, which feemed to be fmall portions of a circle, of which the fun was the center, and of which the diameter feemed to be about forty degrees. Thefe ftreaks confifted only of two colours, red and yellow; the part next the fun was red, and the oppofite part yellow: the fegment that was to the right of the fun difappeared firft, as that part of the fky first became clear; that on the left continued more than half an hour, that part of the fky continuing to be covered with white clouds. Thefe phænomena feem to confirm the opinion of M. Mairan, printed in a memoir of the French academy of sciences in the year 1721, that all parhelia, though very different in appearance, are the fame phanomena as the rainbow, and vary only by local circumftances, which cause them to fade in different portions at different times.

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great violence, but it has been loft many years. The poor man in whofe land it was, miffing the profit he used to have by fhewing it, applied his utmoft endeavours to recover it; but all in vain till May laft, when attending to a rumbling noife under the ground, like what the former well made, though in a lower fituation, and about thirty yards nearer to the river, he happened to hit upon it again.

That you may have some notion what it is, I will lay before you fuch an account of it as the curfory view I had will permit.

The well for four or five feet deep is fix or seven feet wide; within that is another lefs hole of like depth dug in the clay, in the bottom whereof is placed a cylindric earthen veffel, of about four or five inches diameter at the mouth, having the bottom taken off, and the fides well fixed in the clay rammed close about it. Within the pot is a brown water thick as puddle, continually forced up with a violent motion, beyond that of boiling water, and a rumbling hollow noife, rifing or falling by fits five or fix inches; but there was no appearance of any vapour rifing; which perhaps might have been vifible, had not the fun fhone fo bright.

Upon putting down a candle at the end of a ftick, at about a quarter of a yard distance, it took fire, darting and flashing in a violent manner, for about half a yard high, much in the manner of fpirits in a lamp, but with greater agitation. man faid that a tea kettle had been made to boil in about nine minutes time, and that he had left it burning forty-eight hours together without any fenfible diminution.

The

It

It was extinguished by putting a wet mop upon it, which must be kept there a fmall time; otherwife it would not go out. Upon the removal of the mop there fucceeded a fulphurous fmoak. lafting about a minute, and yet the water was very cold to the touch.

The well lies about thirty yards from the Severn, which, in that place, and for fome miles both above and below, runs in a vale full 100 yards perpendicular below the level of the country on either fide, which inclines down to the vale at an angle of twenty or thirty deg. from the horizon, but fomewhat more or lefs in different places, according as the place is more or lefs rocky.

The country confifts of rock, ftone, earth, and clay; and as the river, which is very rapid, washes away the foft and loofe parts, the next fucceffively flip into the channel, fo as by degrees and in time to affect the whole flope of the land; and as the inferior ftrata yield coal and iron ore, their fermentation may produce this vapour, and force it to afcend with violence through the chinks of the earth, and give the water the great motion it has. This might be obftructed in one place by the forementioned fubfiding of the floping bank, and might afterwards find vent in another, in like manner as happened at Scarborough a few years fince.

A gentleman writes, June 16, 1761,

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hole of clay. Other waters had been fuffered to mix with those of the burning fpring, which, though they confiderably diminished the effect, did not however wholly de ftroy it; for upon the application of a piece of lighted paper," a ftream of clear flame fhot up from the well, which very much refembled that of a tea-kettle lamp fed by fpirits; but, as we could not keep out the other water, the flame prefently went out of itself. I forget now to what cause they told us this fhameful neglect was owing; whether to a conteft between two rival claimants to the property, or whether the curiofity of the circumjacent inhabitants, &c. being fully gratified, it no longer attracted a concourfe of vifitants fufficient to reward the attention of the Pro prietor. It were to be wifhed that fome of the gentlemen in that neighbourhood (which I have now left many years) would give us the present state of this wonderful phænomenon.

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town, coming down Wappo creek, refembling a column of fmoak and vapour, whofe motion was very irregular and tumultuous, and came with great swiftness. The quantity of vapour which compofed this impetuous column, and its prodigious velocity, gave fuch a furprifing momentum, as to plough Ash ley river to the bottom, and laid the channel bare: this occafioned fuch a fudden flux and reflux, as to float many boats, pettiaugers, and even floops and fchooners, which were before lying dry, at fome diftance from the tide. When it was coming down Afhley river, it made a noife like conftant thunder; its diameter, at that time, was judged to be about 300 fathoms, and its height about 35 degrees. It was met at White Point by another guft, which came down Cooper's river, but was not equal to the other; but upon their meeting to gether, the tumultuous agitation of the air was much greater, infomuch that the froth and vapour feemed to be thrown up to the height of 40 degrees, while the clouds that were driving in all directions to this place, feemed to be precipitated, and whirled round at the fame time, with incredible velocity. Juft after this it fell upon the fhipping in the road, and was fcarce three minutes in its paffage, though the distance was near two leagues; there were forty-five fail in the road, five of which were funk outright, and his majesty's fhip Dolphin, with eleven others, loft their mafts, &c. The damage done to the shipping, which is valued at 20,000 I. fterling, was done almost instantaneously, and fome of those that were funk, were buried in the water fo fuddenly, as fcarce to give

time to thofe that were below to get upon deck; and it is remarkable, that but four lives were loft in them. The ftrong guft which came down Cooper's river, checked the progrefs of that pillar of deftruction from Wappo creek, which, had it kept its then direction, muft have driven the town of Charlestown before it like chaff. This tremendous column was firft feen about noon, upwards of fifty miles W. by S, from Charles-town, and has deftroyed, in its courfe, feveral houfes, negro huts, &c. on the plantations, and many, both white people and negroes, were killed and hurt; befides many cattle have also been found dead in the fields. In feveral parts of its course it left an avenue of a great width, from which every tree and fhrub was torn up: great quantities of bran ches and limbs of trees were furi oufly driven about, and agitated in the body of the column as it paffed along. The fleet lying in the road ready to fail for Europe, was the largest and richest that ever cleared out from Charles-town. About four o'clock the wind was quite fallen, the fky clear and ferene, fo that it was scarce credible that such a dreadful scene had been fo re cently exhibited, were not the finking and difmafted veffels fo many fhocking and melancholy proofs of it. The finking of the five ships in the road was fo fudden, that it was a doubt whether it was done by the immenfe weight of this colum preffing them inftantaneously into the deep, or whether it was done by the water being forced fuddenly from under them, and thereby letting them fink fo low, as to be immediately covered and ingulphed by the lateral mafs of water. Moft

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