should find himself in the midst of a shoal of | have been an every-day occurrence, that led to the sharks.

In what has been said regarding artificial aids in swimming, we would by no means be understood to advocate the use of such instruments by those who merely enter the water for healthful exercise. Nothing can be better for the purpose than swimming as it is usually practised; and as the accidents that expose us to drowning do not commonly come at convenient times, it would be folly to trust to our having the preventive apparatus always ready. A man is much more likely to have it in his power to save his life by swimming, than by belts and skates; but appliances like the latter possess the same kind of scientific interest we attach to balloons, with a greater probability, as knowledge advances, of becoming practically useful.

From Chambers' Journal.

ARTIFICIAL COLD.

SINCE the days of that dissipated heathen who, in order to cool the air during an oppressive summer, caused mountains of snow to be piled up, and suffered them to melt away, down to the present era, in which there prevails a rage for the thing, mankind has been incessantly in quest of refrigeratives. In those regions where ice and snow are found during winter, it became an easy expedient to store up such treasures of cold for use in warmer seasons; but where, if formed at all, they could only be of a momentary existence, it is manifest that some other means must be devised to supply the luxury of coldness to the noble and wealthy; and thus the art of artificial refrigeration-an art which has to boast of the elaborate researches of the ingenious Robert Boyle, and has occupied much of the consideration of other philosophers before and since -took its origin. We have already taken notice of the now prevalent use and means of procuring beautiful ice for the table: we shall here present a brief sketch of the history, and a short notice of the methods, of producing cold artificially,

next improvement in this method of_refrigeration. Many of the earthen vessels of the Egyptians are made of unglazed ware: water placed in one of these was found to be considerably cooler than when kept in other vessels; and the more open and porous the material, the more rapid the transudation of the water, and its evaporation from the surface of the jars, and the greater the degree of cold obtained. Water-vases were then formed for that purpose solely; and the invention, unaltered in principle, has come down with increasing usefulness to the present time. Illustrations of the second great chemical law-that liquefaction produces cold-next followed. For ages in India, it had been the practice to cool beverages in that burning climate by dissolving saltpetre in water. From India the practice made its way into Europe; and Beckmann states that a Spanish physician, Blarious Villa Franca, practising at Rome, first introduced this method of producing cold in Italy about the middle of the sixteenth century. It is related that wine, placed in this mixture, was cooled to a degree making it almost intolerable to the teeth; and this was a considerable step in the history of artificial cold. Other saline substances came into use, and pits were formed, into which, on the large scale, the water to be cooled was put in vessels, surrounded by the cooling mixture. Finally came the important discovery, that an intensely freezing mixture was capable of being formed by mixing snow or ice and salt together. A celebrated physician electrified a large audience by exhibiting its effects upon a bottle of wine, which he actually froze into ice; and "this new method of freezing water" is also mentioned by Lord Bacon. Such are the conditions under which this subject has been handed down to existing posterity.

A little consideration of the processes described in this cursory sketch, of the chemical progress of the luxury, will show us that they are all reducible to the two axioms-that evaporation and liquefaction create cold. The philosophy of which fact is Cold, as a luxury, was far from being unknown simply, that in the change of condition from a fluid to the ancients. The winter's snow or ice was to a vapor, and from a solid to a fluid, there is a rudely gathered up in heaps, or buried in pits, and change in the capacity for caloric. If a certain covered with straw or chaff. But this was a waste- measure of water is to become vaporized, or if a ful, and grew to be an expensive method; and it certain weight of salt is to become a solution, these became desirable to have ready means at every sea- changes cannot occur without the water and the salt son, and independently of the accidents of the skies, receiving an additional supply of heat, which is of for obtaining the same end. The simplest of these course abstracted from all surrounding bodies; and proceeded on the principle of loss of temperature, the abstraction of heat being an equivalent expres as a result of rapid evaporation. The Egyptians sion to the production of cold, we are brought back were accustomed to cool their water by placing it in to the truths with which we commenced, and have earthen pitchers, the exterior of which was kept seen how evaporation and liquefaction produce cold. constantly wet by being sprinkled with water by | Caloric disappears in both cases, and, burying itself slaves. It was the habit of one of their luxurious monarchs to have several servants for this office alone, whose duties were to expose the water to cool on the summit of the palace, and constantly supply the royal table with the beverage. Cooling pits were also dug in the earth, into which the water-vessels were placed during the daytime; the exterior being well soaked with water, and then surrounded with the fresh leaves of a vine or other plant, evaporation rapidly went on, and the liquid became most agreeably cool. Another method is said to be mentioned by Plutarch, which was by casting into the water a number of small stones, the agitation and consequent evaporation produced by which would probably exercise a slightly frigorific power over the water. It was probably an accidental observation of what could not have failed to

among the particles of the new product, is said to have become latent. There are some facts connected with the production of artificial ice which deserve mention here. The congelation of water is materially promoted by rapid motion. Water has, in fact, been cooled, and yet remained quite fluid, many degrees below the temperature at which it generally becomes ice; but the moment a little movement was communicated to the liquid, instantly the temperature rose to 32 degrees, and the mass became ice, needle-like crystals flying through its substance in a most curious manner, This fact was seized upon by the refrigeratists, and repeated accounts of making artificial ice are extant, in which much stress is evidently laid upon the act of stirring the fluid to be frozen rapidly round with a stick. The experience of mankind also appears to have discovered

From Chambers' Journal.

AIDS IN SWIMMING.

therefore, that so many plans have been tried for obtaining an independent buoyancy. Every season we hear of some new invention with reference to this grand desideratum; for the attempts that were formerly made to increase the force of the swimmer's movements appear to be abandoned as chimerical. The gloves, for instance, with web fingers, are quite unsuited to our muscular power, which finds the resistance offered by the water to our naked hand quite great enough. The same thing may be said of the attempts to provide the feet with similar contrivances, intended to expand when shoved against the water, and to close at the return. But we are not sure that the "swimming skate,” invented in France a few years ago, has attracted so much attention as it would seem to deserve, from the circumstance of its being the only contrivance (so far as our knowledge of the subject goes) the effect of which is to place man, when swimming, in his usual walking attitude.

The swimming skate is a piece of wood, furnished with two parallel rows of plates, folding over each other, so as to resemble in some degree the laths of a blind. These open or shut, according as the foot to which the skate is attached moves downwards or upwards; and the swimmer advances by the alternate motion of his limbs, as in mounting a

in skating. By the aid of this instrument, he is able, it is said, to remain stationary in the water; but we presume this can only be for a short determinate time. At any rate, he can turn in any direction he pleases, raise himself out of the water as high as the girdle, and continue the exercise almost as long as that of walking. In order to plunge to the bottom, he has only to raise himself, by quick motions of his limbs, as high above the surface as possible, and then point the toes downwards.

SOME persons have supposed that the only reason why a man, however unaccustomed to the water, does not swim as well as one of the lower animals, is, that the former has more dread of the foreign element; and they assert that all we have to do, in order to float, is to discard fear, and trust implicitly to the natural buoyancy of our bodies. But this comfortable theory is at most not more than half true. When one of the lower animals finds himself in the water, he is in his natural posture for movement, and plies his feet to escape from the danger, just as he would on land in the action of running. Man, on the contrary, if he would use the four paddles with which nature has provided him, must throw himself prone on his face, abandon all his usual habits of motion, and attempt to push himself on against the water with his palms and soles, and at the same time manage in such a way, when drawing them in for a new stroke, as to prevent the preceding effort from being neutralized. Swimming, therefore, is an instinct with the brute, but an art with the man. That fear, however, impedes the progress of a man in learning to swim, is perfectly true. It deprives him of the presence of mind necessary for acquiring an art in circum-stair, keeping the head and body a little forward, as stances of apparent danger; while the very same feeling gives added energy to the instinctive motions of the brute. Many tribes of horses and dogs are vastly more timid than man; and the only reason why the former move with comparative safety in the water is, that in the action of swimming they have merely to obey a natural impulse. When the writer of these lines was a boy, some pains were taken to teach him to swim, and he acquired without much difficulty the theory of the art. But the practice was quite another thing: he no sooner raised his feet from the ground, than down he sank like a stone, till he at length believed that some physical peculiarity rendered swimming an impossibility for him. The peculiarity, however, turned out to be moral, not physical. One day, on the shores of one of the Western Islands, he was bathing in the company of a huge Highlander, and having laid his clothes upon the cliff, was about to descend to a little creek, where the water was smooth and shallow, and the sand soft and white. In front of the rocks was a natural basin, in which a frigate might have swam, with the circling sands of the beach at some little distance beyond; and into this basin rolled the smooth majestic swell of the Atlantic. When about to descend, he was caught up by the giant, and pitched over the cliff like a clod, and found himself, with a shout of mingled wrath and terror, struggling in the hitherto impracticable element! Now, had he not previously learned to swim, he must have sunk, or owed his extrication to his well-meaning friend; but being acquainted with the art, he did swim, like a duck, to the opposite sands-although so little grateful was he for the lesson he had now been taught, that his supposed inability was mere cowardice, that the first thing he did, on regaining his feet, was to fire a volley of stones at his instructor.

We presume it is some instrument like this which assists in the exhibition, not uncommon in this country, termed "walking in the water;" but the experiment of adding to the swimming skate the inflated cape or belt might be worth trying. The latter, and all similar contrivances, however valuable, as affording the means of floating, rather diminish the facility of motion than otherwise, from the addition they make to the volume of the body. The grand thing to be sought after is the power of movement through the water, in union with perfect safety in the water: the latter we cannot think derivable from the skates alone, while without them, the accidental rupture of the air-vessels would be fatal.

The part which the lower animals take in this question reminds us that, as among them there are tribes even of the same species better adapted for swimming than others, so there may be families of mankind that take to the water as naturally as Newfoundland dogs. This is affirmed by Sir George Simpson of the Sandwich islanders, who, he says,

may almost be said to be born swimmers; for they actually take the water before they leave the breast. At Lahaina, in particular, I was highly amused with the early development of this innate talent. Through the town there runs, or rather creeps, a sluggish streamlet, into which urchins that Everybody knows that to persons well acquainted were hardly able to stand used to crawl on all fours; with the art, it is possible to rest for a certain time but no sooner did they gain the congenial element, in swimming, by lying upon the back; but this can than they struck out like a young fish, diving, and only be done in perfectly smooth water; and in ducking, and performing a variety of feats with conother attitudes, the body, however great its buoy-fidence and ease." The art, thus early learned, is ancy, must be kept constantly trimmed by the mo- highly important in after-life; for if an islander on of the hands and feet. It is not surprising, founders at sea, he is quite undisturbed even if he

that water, after it has been boiled, freezes more | ates a very useful degree of cold; and where the rapidly than otherwise. It is a custom among many salt is plentiful, as in India, it has long been emnations of warm climates either to warm the water ployed for this purpose. It was the peculiar duty in the sun, or to boil it, previous to attempting to of one domestic to cool beverages for the table by reduce its temperature. Dr. Black of Edinburgh this means, who received the impregnated solution published some experiments undertaken to deter- for his perquisite. Where, however, snow or ice mine the question; and his results were, that boiled is procurable, the intensity of the freezing mixture water does freeze a little more rapidly than unboiled. rises to its higher points. Snow and salt produce The act of boiling expels the air; and as in freezing a mixture which was deemed by Fahrenheit to be a similar expulsion takes place, a step is gained in of the greatest possible degree of cold. This was advance of the unboiled liquid. the temperature of his zero. Our confectioners are The means in present use for artificial refrigera- in the habit of using for their craft a mixture of tion are very various, some of them very interesting. pounded ice and salt. The substance known as Among these, the employment of porous earthen-chloride of calcium, mixed with snow, produces a ware may receive an early place. The Moors most severe cold, sufficiently great to freeze inerintroduced into Spain this article of luxury, in the cury. Mr. Walker, to whose interesting experishape of very elegant vases, wonderfully light and ments upon this subject it stands much indebted, porous. Water kept in these became rapidly de- was on one occasion able, by successive coolings, to liciously cool, and, from some peculiarity in the attain a depth of cold equal to 91 degrees below process of the manufacture of the vessels, it ac- Fahrenheit's unhappy zero. In the laboratory of quired, in addition, a very agreeable flavor. In the chemist, great degrees of cold are procurable Egypt, and in India, and in most sultry regions, by the use of highly volatile liquids for evaporation. this expedient is at the present time a very prevalent Every juvenile chemist's ears have tingled with the one. It has also for some time been extensively startling enunciation of the possibility of freezing a employed amongst ourselves-porous wine, butter, man to death in the height of summer, by wetting and water coolers, of many elegant designs, being him constantly with ether-which is, however, a now produced at our potteries. But porous ware fact hitherto undemonstrated. The sulphuret of keeps water coolest where the clime is hottest, the carbon, and, more recently, liquid sulphurous acid, very increment of heat being made to react in the both of them exceedingly volatile fluids, create production of cold by rapid evaporation. The Moor-intense cold by their evaporation. The almost ish name for their earthen jugs was Alcarrazos, or magical experiments of M. Boutigny, in which Bucarros. The Arabs, burnt up with the eternal water was frozen in a red-hot crucible, were effected fire of their scorching country, make use of goat- by the assistance of sulphurous acid in the liquid skins for their water-vessels, which suffer a little form. The remarkable substance, liquid carbonic water slowly to exude, and thus keep the remain- acid, takes the highest rank as a refrigorific agent der comparatively cool. A common method of known. Mr. Addams of Kensington actually mancooling wines in India is one which will almost ufactures this curious liquid as an article of comappear a paradox: the bottle is wrapped in flannel merce, and has occasionally as much as nine gallons wetted with water, and placed directly in the rays of it in store. In drawing it from its powerful reserof the sun violent evaporation ensues, and the voirs, it evaporates so rapidly as to freeze itself, and wine actually becomes very cold. It is a common it is then a light porous mass, like snow. If a small plan, too, for sailors, in warm latitudes, to cover quantity of this is drenched with ether, the degree their wine with cloths constantly wetted. Apart- of cold produced is even more intolerable to the ments are cooled on a similar principle, and an touch than boiling water! a drop or two of the abundance of water is frequently dashed against the mixture producing blisters, just as if the skin had walls of the room with the most grateful effect. In been burned. Mr. Addams states, that in eight India, also, the cold, so dangerous and penetrating minutes he has frozen in this way a mass of mercury on a clear night, is applied in a peculiar manner for weighing ten pounds. the purpose of freezing water. Near Calcutta, in an open plain, there are large shallow excavations made in the ground, and filled with straw; upon this many rows of small, shallow, porous pans, filled with water, are placed at sunset. During the night ice forms in thin cakes upon the surface of these pans it is carefully removed before sunrise, carried to a proper repository, and pounded into a mass there, and then covered over with blankets. This manufacture can only be pursued during the months of December, January, and February; and in the districts where the ice is formed in this manner, it is never produced naturally. This ingenious process must wholly disappear before the new import of Wenham Lake ice. What a revolution has commerce effected in India, when we remember that early travellers in that country were looked upon as liars and impostors for asserting the possibility of solidifying water into ice!

There have been some mechanical contrivances for the manufacture of ice. Evaporation may be accelerated mechanically to a degree so great as to produce ice in considerable quantities; and this is the principle of Sir John Leslie's celebrated freezing apparatus. In conducting some experiments upon the rarefaction of air, he was led to conceive the idea of manufacturing ice on the large scale from a little phenomenon observed in the receiver of his air-pump. Introducing a watch-glass full of water, and in contact with sulphuric acid, into the receiver of his air-pump, and on making a few strokes with the piston, the water was converted into a mass of solid ice! With a body of parched oatmeal instead of the acid as the absorbent of moisture, he froze a pound and a quarter of water into ice. Experiments on the large scale followed; powerful machines were constructed, and various improvements were adopted in the apparatus, all tending to facilitate its application to the wants or luxuries of mankind. Several of these machines have been exported into hot climates. Dr. Ure suggested steam as the term cold is made use of, for convenience' sake, as if it

indicated a positive principle, and were not, as it is, a mere negation.

vacuizing power; and the idea has been conceived, | our men have grown ashamed of their pig-tailed that wherever a steam-engine is employed, there an coats, not a thread of which will survive for their ice apparatus might be erected and sustained at a heirs at law. Already, in like manner, do we trifling cost, with great prospect of productiveness. begin to pick up little thieves and beggars from the The most recent ice-machine is "Masters' Ap-streets, to imprison them in schools, instead of conparatus," the principal feature of which is, that a taminating them in jails; to turn them to knowledge metallic cylinder is made to undergo rapid rotation and industry, instead of confirming them in ignoin a freezing mixture, the motion appearing in a rance and crime; and to lead them on to public singular manner to expedite and facilitate the pro- usefulness, rather than the hulks and the gallows. Condemn not, therefore, the vulgar-genteel, any more than our ancestors, for, like the latter, they are pilgrims on the road, and their very errors are paths that lead to truth.

cess.

Some account of the applications of artificial cold may perhaps suitably conclude our paper. For some time the ingenuity of men in this particular developed itself no further than in simply cooling But there is one thing in the general bearing and wine and other beverages; but a more refined and tendency of the present age towards the Genteel even elegant mode of doing so was afterwards dis- which is a little puzzling-not that we think the covered. In Boyle's "History of Cold," it is stated thing unnatural or improper in itself, but we cannot that he was accustomed to make wine-cups of ice, well see in what way the result is to benefit society. by means of tin moulds, for use in hot weather: Gaudy or ill-matched colors betray a mental strugpleasant trifles, as he calls them, which imparted a gle, which may end in advancing the individual in delicious coolness to the wine poured into them. In the path to taste; and a control, however rude, of an old romance, named the "Argenis," a dinner in the language and movements of the body, may in summer is described, at which fresh apples half-like manner result in an approach towards politeincrusted with ice, and a basin of ice filled withness. But of what utility in our social progress is wine, were among the curiosities upon the table. the present chronic revolution in proper names? Then came the invention of water-ices by one Procope, an Italian, who had an immense sale for them in Paris. Cream ices, and the iced juice of fruits, were then made, and found a rapid consumption. More recently, the art of the confectioner has applied this process to imitate many kinds of fruit and peaches-apricots and nectarines of ice-copying the originals with curious fidelity.

THE ARISTOCRACY OF NAMES.

Suppose, for instance, the whole race of Smiths get on to writing their name Smyth, or even reach the ne plus ultra Smythe, cui bono? Smythe is not intrinsically better than Smith; it is only more uncommon; and every advance the multitudinous tribe makes in this direction defeats its own object. If Smythe were a good, or a beauty in itself-if it were the beau ideal of Smith-that would be another thing; but it does not even make the name a dissyllable—it leaves it the same short, squat, ruturier word as ever. Nothing, in fact, can be done for Smith but giving it an amiable prename, or, better still, a title. Sir Sidney Smith, for instance, has a decidedly aristocratic sound; and this has no dependence upon its personal assonized as the legitimate chief of the clan. Without a prename at all, Count Smith, and Baron Smith, so common on the continent, are highly respectable; and if a suggestion had been adopted, which was kindly and happily made, on the occasion of the marriage of an Irish beauty of the name with a scion of Italian royalty, Smith would have become As a familiar illustration of what we mean the one of the most distinguished patronymics in the philosopher smiles at the enthusiasm of the vulgar kingdom. The match alluded to was reckoned a in their aspirations after an undefined and undefin-mesalliance on the part of the lover, who was acable good they call the Genteel; but the philoso- cordingly threatened to be discarded by his family; pher may smile on, for the wisdom of the learned and he was therefore advised to confer upon the Theban is foolishness. Such aspirations are the name of his lovely bride his own title, and call beginning of all refinement. They lead, it is true, himself Prince Smith. to the perpetration of innumerable caricatures; but these in time correct themselves, or are corrected by collision, till every day some individuals, rising gradually above the mass, ascend into the region of true taste or what is taken for such by the present generation. And what is true of individuals, is true of nations, and of society at large. The history of manners and costume, or, so to speak, Fashion, is the history of virtue and intelligence. How many revolutions have we passed through, before reaching our present simplicity of attire! And how many horrors have we encountered, before subsiding into our present condition of comparative charity and peace! Our contemporaries are better, as well as better dressed, than their ancestors; and our posterity will be better, and better dressed, than ourselves. Already our women have more elegance, and less bustle; and already

OUR readers are aware that the strange thesis has been maintained before now that "private vices are public benefits;" and some may have wondered at the desperate ingenuity which could work evil into good by the simple rule of multiplication.ciations, otherwise Adam Smith would be recogBut we live in a world of seeming anomalies; and however difficult their reconciliation may be, there is no doubt that the errors of individuals are overmastered in their collective tendency, and that we all, good, bad, wise, and foolish alike, cöoperate unconsciously, in the great work of human progress.

But even a prename alone may be of great advantage. There is one of the novels of Miss Edgeworth-we forget which-in which a gentleman of the name of Harvey figures as the hero. Harvey! Only fancy John, Peter, or even William Harvey as the hero of a novel! But Miss Edgeworth was too well acquainted with the philosophy of names to commit such a blunder: she made the individual Clarence Harvey; and the name has never to this day been objected to even among the female teens. Our own attention was first attracted to the importance of names by the case of an adventurer in London whom we knew personally. He was a countryman of the Princess Smith alluded to, and had come up to push his fortune in the musical line. Being really a person of fair abilities, he obtained a few pupils, and had even a couple of little songs published by the music-sellers; but it would not do.