Since her recefs from her parental abode, the old couple had determined, in mere fpite, to be revenged of her obftinacy, as they termed it, to spend eve ry fhilling of their property; and the fteps they took towards it were fo effectually forwarded by their numerous train of fycophants, that they were already reduced to the humiliating neceffity of univerfal retrenchments, in order to preserve the wreck of their once ample fortune, for future fubfiftence. It was now that every face came forward from behind it's mask, and the fubtle fneer of irony was fucceeded by the broad laugh of public derifion.

Unable either to support their ufual expences, or to bear up against the ftings of daily ridicule, poor old Nimrod and his confort were forced to hide their diminished heads in the bosom of obfcurity, and the Bath villa was difpofed of to as little advantage as credit.

Forgetful of all the injuries fhe had received, the ever-dutiful Eliza no fooner heard of this catastrophe, than the determined to fly to their relief. Horatio accompanied her on this occafion; nor could he be prevailed on to leave behind her the blooming pledge fhe had bore him of their mutual and faithful loves.

It was not till after many enquiries that she discovered the retreat to which the old couple had retired, and where they still endeavoured to keep up at leaft the fhadow of their former confequence. Old Nimrod still valued himfelf on his pedigree as much as ever, and not a day paffed without the addition of fome new name to the lift. Eliza entered the apartment in which they were, without the formality of fending up her name; when falling on her knees, and prefenting her child, whom the held by the hand, fhe for fome moments in vain attempted to Speak, overcome by the violence of her feelings.

So! fo!' exclaimed the father, miftaking the real cause of her embarraffment; what, I fuppofe, Mifs, your heroic gallant has played you the old trick of feduction; and now

True, fon-in-law; true!' anfwered Nimrod, trembling in every limb; I believe I am to blame, as well as my lady here; and I humbly afk you and my daughter pardon. As I live, 6 now, you feem to be a clever fellow and had you but a pedigree

Tufh! tuh!' faid Horatio fmiling, producing one which he had purposely. drawn up at the request of Eliza, in compliance with her father's humour; here, Sir, is a pedigree every way authentic, of which the firft peer of the ⚫ land need not be afhamed!'

Old Nimrod fpread the vellum on the table by the fide of that which already lay there; and, embracing Horatio with the moft eager tranfport, ByHeaven!' he exclaimed, 'you must be a clever fellow; for your pedigree • is within a foot of being as long as my own.'

Horatio foon gave the old couple more fubftantial reafons for being fatisfied with the conduct of their fon-inlaw, by allowing them an annual ftipend, adequate to all their exigencies, for the reft of their days. They both lived to fee and correct the extravagance of their former follies; whilft the example of Horatio taught them to fet a juft value on thofe virtues which ftill continue to embellish their amiable daughter.

T is at prefent well known, that

a fenfible degree of cold is produced; and that by the evaporation of ether, which is the most volatile fluid we are acquainted with, water may be congealed, and the thermometer may be brought feveral degrees below the freezing point. But as various thermometrical experiments, which I lately made, have exhibited fome new phenomena, and as I have contrived an eafy and pleafing method of freezing a fmall quantity of water in a fhort time, and in every climate; I think it not improper to give an account of these things in the first part of this le&ture.

My firft experiments were intended to discover, if poffible, a fluid cheaper than ether, by the evaporation of which a degree of cold fufficient for fome ufeful purpofe might be gene. rated. But in this my expectation was disappointed, as I found that ether was incomparably fuperior to any other fluid, as the cold it produced was several degrees greater than that occafioned by any other of the moft volatile fluids whatever. Being therefore obliged to use ether, I endeavoured to contrive a method by which the leaft poffible quantity of it might be wafted in the production of a degree of cold fufficient to freeze water, and in this I met with fuccefs. But before we come to the defcrip. tion of this method, I fhall briefly relate fome obfervations made on the cold produced by the evaporation of other fluids befides ether. VOL. III.

In a room, the temperature of which was 64 degrees, according to Fahrenheit's thermometer, and in which the air was gently ventilated, I obferved the effects produced by various fluids when thrown upon the ball of a thermometer. The ball of this thermometer was quite detached from the ivorypiece upon which the scale was engrav ed. The various fluids were thrown upon the thermometer through the capillary aperture of a small glafs veffel, haped like a funnel, and care was taken to throw them so slowly upon the bulb of the thermometer, that a drop might now and then fall from the

fluids were ufed, which evaporate very flowly, in which cafe it was fufficient to keep the ball of the thermometer only moist, without any drop falling from it. During the experiment the thermometer was kept turning very gently round it's axis, in order that the fluid ufed might fall upon every part of it's bulb. This method I find to answer much better than that of dipping the ball of the thermometer into the fluid and removing it immediately after, or that of wetting_the thermometer with a feather. evaporation, and confequently the cold produced by it, may be increased by ventilation. viz. by blowing with a pair of bellows upon the thermometer; but this was not used in the following experiments, because it is not eafily performed by one perfon, and alfo because it occafions very uncertain refults.

The

With the above defcribed method I began to examine the effects of water, and found; that the thermometer was brought down to 56 degrees, viz. 8 degrees below the temperature of the room in which the experiment was made, and of the water employed. This effect was produced in about two minutes time, after which a larger continuation did not bring the mercury lower.

By means of fpirit of wine the thermometer was brought down to 48 degrees, which is only 16 degrees below the temperature of the room, and of the spirit employed. When the fpi2 X

rit

rit of wine is highly rectified, the cold produced by it's evaporation is certainly greater than when it is of the common fort; but the difference is not fo great as one who never tried the experiment might expect. The purer fpirit produces the effect much quicker.

Ufing various other fluids, which were either compounds of water and fpiritous fubftances, or pure effences, I found that the cold produced by their evaporation was generally in fome intermediate degree between the cold produced by the water and that produced by the fpirit of wine.

Spirit of turpentine brought the thermometer only 3 degrees lower than the temperature of the room; but olive oil and other oils, which evaporate either very flowly or not at all, did not fenfibly affect the ther

mometer.

Willing to obferve how much electrization could increase the evaporation of fpirit of wine, and confequently the cold produced by it, I put the tube containing the spirit into an infulating handle, and connected it with the conductor of an electrical machine, which was kept in action whilft the experiment was performed; by these means the thermometer was brought down to 47 degrees. Haying tried the three mineral acids, I found that, inftead of cooling, they heated the thermometer, which effect I expected, fince it is well known, that those acids attract the water from the atmosphere, and that heat is produced by the combination of water and of them. The vitriolic acid, any which was very ftrong and tranfparent, raised the thermometer to 102 degrees; the fmoaking nitrous acid railed it to 72 degrees; and the marine acid raised it to 66 degrees; the temperature of the room, as well as of the acids, being 64 degrees, as mentioned above.

The apparatus which I contrived for the purpose of ufing the leaft poffible quantity of ether in freezing wa ter, &c. confifts in a glass tube, termi nating in a capillary aperture, which

tube is to be fixed upon the bottle that contains the ether. When the experiment is to be made, the stopper of the bottle containing the ether is removed, and the above-mentioned tube is fixed upon it. The thread round this tube fhould be moistened a little with water or spittle before it is fixed on the bottle, in order to prevent more effectually any escape of ether between the neck of the bottle and the tube. Then holding the bottle by it's bottom, and keeping it inclined, the small stream of ether iffuing out of the aperture of the tube is directed upon the ball of the thermometer, or upon a tube containing water or other liquor that is required to be congealed.

Ether being very volatile, and having the remarkable property of increafing the bulk of air, does not require any aperture, through which the air might enter the bottle, in proportion as the ether goes out: the heat of the hand is more than fufficient to force the ether in a stream from the aperture.

After this manner, throwing the ftream of ether upon the ball of a thermometer in fuch quantity as that a drop of ether might now and then, for inftance every 10 feconds, fall from the under part of the thermometer, I have brought the mercury down to 3 degrees, viz. 29 degrees below the freezing point, when the atmosphere was fomewhat hotter than temperate, and that without blowing upon the thermometer.

When the ether is very good, viz. is capable of diffolving elaftic gum, and the thermometer has a small bulb, not above twenty drops of ether are required to produce this effect, and about two minutes of time; but when the ether is of the common fort, a greater quantity of it, and a longer time, are neceffary to be employed, though at laft the thermometer is brought down very nearly as low by this as by the best fort of ether.

In order to freeze water by the eva poration of ether, I take a thin glass tube about four inches long and about

one

one-fifth of an inch in diameter, hermetically closed at one end, and put a little water in it, fo as to fill about half an inch length of it. Into this tube a flender wire is alfo introduced, the lower extremity of which is twisted in a fpiral manner, and ferves to draw up the ice, when formed. Things being thus prepared, I hold the glafs tube by it's upper part with the fingers of the left-hand, and keep it continually and gently turning round it's axis, firft one way, and then the contrary; whilft with the right hand I hold the phial containing the ether in fuch a manner as to direct the stream of ether on the outfide of the tube, and a little above the furface of the water in it. The capillary aperture fhould be kept almoft in contact with the furface of the tube that contains the water. Continuing this operation for two or three minutes, the water will be froze as it were in an inftant; fince it will appear to become opaque at the bottom, and the opacity will afcend in less than half a fecond of time, which exhibits a beautiful appearance. This congelation, however, is only fuperficial, and in order to congeal the whole quantity of water, the operation must be continued one or two minutes longer; after which the wire will be found to be kept very tight by the ice. Now the bottle with the ether is left upon a table or other place, and to the outfide of the glass-tube the hand must be applied for a moment, in order to foften the furface of the ice, which adheres very firmly to the glafs, and then pulling the wire out of the tube, a folid and hard piece of ice will come out, faftened to it's fpiral extremity. Instead of the wire, fometimes I put a fmall thermometer into this tube fo as to have it's bulb immersed in the water. With this thermometer I have obferved a very remarkable phenomenon, which feems to be not explicable in the present state of knowledge concerning heat and cold. This is, that water will freeze in the winter with a lefs degree of cold than it will in the fummer, or when the weather is

hotter: for instance, in the winter, the water in the tube will freeze when the thermometer is about 30 degrees; but, in the fummer, or even when the temperature of the atmosphere is about 60 degrees, the quickfilver in the thermometer must be brought ten or fifteen, or even more degrees below the freezing point, before the water which furrounds the faid thermometer will be converted into ice, even fuperficially; hence it appears, that in the fummer-time a greater quantity of ether and longer time are required to freeze a given quantity of water than in the winter, not only because then a greater degree of heat is to be overcome, but principally because in the fummer a much greater degree of cold must be actually produced before the water that is kept in it will affume a folid form. When the temperature of the atmosphere has been about 40 degrees, I have froze a quantity of water with an equal weight of good ether; but at prefent, being fummer, between two and three times the quantity of the fame ether must be used to produce the fame effect.

There seems to be fomething in the air which, befides heat, interferes with the freezing of water, and perhaps of all fluids, though I cannot fay from experience whether the abovementioned difference between the freezing of water in winter and fummer, takes place with other fluids, as milk, and other animal fluids, oils, wines, &c.

The proportion between the quantity of the ether and of the water that may be frozen by it, feems to vary according to the quantity of water; for a larger quantity of water feems to require a proportionably lefs quan tity of ether than a fmaller quantity of water, fuppofing that the water is contained in cylindrical glafs veffels; for I have not tried whether a metal veffel instead of a glafs one, and whether fome other shape befides the cylindrical, might not facilitate the congelation. In the beginning of the fpring, I froze about a quarter of an ounce of water with nearly half an 2 X 2

ounce

ounce weight of ether, the apparatus being larger, though fimilar to that defcribed above.

Now, as the price of ether, fufficiently good for the purpose, is generally between eighteen-pence and two fhillings per ounce, it is plain that, with less than two fhillings, a quarter of an ounce of ice, or ice-cream, may be made in every climate, and at any time; which may afford great fatisfaction to thofe perfons who, living in places where no natural ice is to be had, never faw or tafted any fuch delicious refreshments.

When a small piece of ice, for inftance, of about ten grains in weight, is wanted, the neceffary apparatus is very small, and the expence of the ether not worth mentioning. I have a fmall box, which is four inches and a half long, two inches broad, and one inch and a half deep, which contains all the apparatus neceffary for this purpose, viz. a bottle capable of containing about one ounce of ether, two pointed tubes, (in cafe that one fhould break) a tube in which the water is to be frozen, and the wire. With the quantity of ether contained in this fmall and very portable apparatus, the experiment, when carefully performed, may be repeated about ten times. A perfon who wishes to perform fuch experiments in hot climates, and in places where ice is not eafily procured, requires only a large bottle of ether, befides the small apparatus defcribed above.

It is a known fact, that the moment a quantity of water becomes ice, a thermometer kept immerfed in it, rifes a few degrees; and accordingly this is obferved in our experiment, viz. the mercury of the thermometer, which is immerfed in the water of the tube, will fuddenly rife, fometimes as much as ten degrees, when the water becomes firft opaque. Electrization increases very little the degree of cold produced by the evaporation of ether. Having thrown the electrified, and also the unelectrified, ftream of ether upon the bulb of a thermometer, the mercury in it was brought

down two degrees lower in the former than in the latter cafe.

As various perfons may, perhaps, be induced by this paper to repeat fuch experiments, and as ether is a fluid which can with difficulty be preferved, it may be useful to mention, that a cork confines ether in a glass bottle much better than a glafs topple, which it is almoft impoffible to grind fo well as entirely to prevent the evaporation of ether. When a ftopple made very nicely out of a uniform and clofe piece of cork, which goes rather tight, is put upon a bottle of ether, the fmell of that fluid cannot be perceived through it; but I never faw a glafs ftopple that could produce the fame effect. By opening the bottle very often, or by long keeping, the cork becomes loose, in which cafe it must be changed; and thus, ether, fpirit of wine, or any fluid, excepting those which corrode cork, may be preferved.

I fhall now defcribe a method of purifying vitriolic ether, which is very eafy and expeditious, though not very profitable. Fill about a quarter of a ftrong bottle with common ether, and upon it pour about twice as much water, then ftop the bottle, and give it a fhake, fo as to mix for a time the ether with the water. This done, keep the bottle without motion, and with the mouth downwards, till the ether is feparated from the water, and swims over it, which requires not above three or four minutes of time; then open the bottle, and keeping it ftill inverted, let the greatest part of the water come out very gently; after this the bottle being turned with the mouth upwards, more water must be poured in it, and in fhort the fame operation must be repeated three or four times. Laftly, all the water being separated from the ether by decanting it with dexterity, the ether will be found to be exceedingly pure. By this means I have purified common vitriolic ether, which could not affect elastic gum, and have reduced it into fuch a state as that elaftic gum was eafily diffolved by it.

Indeed,