Читать книгу A History of Inventions, Discoveries, and Origins, Volume II (of 2) - Johann Beckmann - Страница 12

The art of preserving snow for cooling liquors during the summer, in warm countries, was known in the earliest ages. This practice is mentioned by Solomon364, and proofs of it are so numerous in the works of the Greeks and the Romans, that it is unnecessary for me to quote them, especially as they have been collected by others365. How the repositories for keeping it were constructed, we are not expressly told; but what I know on the subject I shall here lay before the reader.

That the snow was preserved in pits or trenches, is asserted by many366. When Alexander the Great besieged the city of Petra, he caused thirty trenches to be dug and filled with snow, which was covered with oak branches, and which kept in that manner for a long time367. Plutarch says that a covering of chaff and coarse cloth is sufficient368; and at present a like method is pursued in Portugal. Where the snow has been collected in a deep gulf, some grass or green sods, covered with dung from the sheep-pens, is thrown over it; and under these it is so well preserved, that the whole summer through it is sent the distance of sixty Spanish miles to Lisbon369.

When the ancients therefore wished to have cooling liquors, they either drank the melted snow or put some of it in their wine, or they placed jars filled with wine in the snow, and suffered it to cool there as long as they thought proper. It appears that in these trenches it could not remain long clean; on the contrary, it was generally so full of chaff, that the snow-water was somewhat coloured with it, and had a taste of it, and for this reason it was necessary to strain either it or the wine that had been cooled by it370.

That ice also was preserved for the like purpose, is probable from the testimony of various authors371; but it appears not to have been used so much in warm countries as in the northern. Even at present snow is employed in Italy, Spain, and Portugal; but in Persia, ice372. I have never anywhere found an account of Grecian or Roman ice-houses. By the writers on agriculture they are not mentioned.

Mankind however soon conceived the idea of cooling water without snow or ice, from having remarked that it became cold more speedily when it had been previously boiled, or at least warmed, and then put in a vessel among snow, or in a place much exposed to the air. Pliny seems to give this as an invention of Nero373; and a jocular expression in Suetonius374 makes it at any rate probable that he was fond of water cooled by this method; but it appears to be much older. It seems to have been known even to Hippocrates: at least Galen375 believes so. And Aristotle376 was undoubtedly acquainted with it; for he says that some were accustomed, when they wished water to become soon cold, to place it first in the sun and suffer it to grow warm. He relates also that, the fishermen near the Black Sea poured boiling water over the reeds which they used in fishing on the ice to cause them to freeze sooner. Galen377 on this subject is still more precise. He informs us that the above practice was not so much used in Italy and Greece, where snow could be procured, as in Egypt and other warm countries, where neither snow nor cool springs were to be found. The water after it had been boiled was put into earthen vessels or jars, and exposed in the evening on the upper part of the house to the night air. In the morning these vessels were put into the earth (perhaps in a pit), moistened on the outside with water, and then bound round with fresh or green plants, by which means the water could be preserved cool throughout the whole day. Athenæus378, who gives a like account from a book of Protagorides, remarks, that the pitchers filled with water, which had become warm by standing all day long in the sun, were kept continually wet during the night, by servants destined to that office, and in the morning were bound round with straw. In the island of Cimolus379, water which had become warm in the day-time was put into earthen jars, and deposited in a cool cellar, where it grew as cold as snow. It was generally believed therefore, that water which had been warmed or boiled, was soonest cooled, as well as acquired a greater degree of refrigeration; and on this account boiled water is mentioned so often in the works of the ancients380.

The same opinion prevails at present in the southern countries of Asia, and people there still let their water boil before they expose it to the air to cool381. The experiments however which have been made on this subject by philosophers, have proved very different in the result. When one indeed places boiling and cold water, all other circumstances being equal, in frosty air, the latter will become ice before the former has cooled; but when one exposes to the cold, water that has been boiled, and unboiled water of equal temperatures, the former will be converted into ice somewhat sooner.

The experiments made by Mariotte382, Perrault383, the Academy del Cimento384, Marian385 and others, showed no perceptible difference in the time of freezing, between boiled and unboiled water; but the former produced ice harder and clearer, the latter ice more full of blisters. In later times, Dr. Black of Edinburgh has, from his experiments, asserted the contrary. Boiled water, he says, becomes ice sooner than unboiled, if the latter be left at perfect rest; but if the latter be stirred sometimes with a chocolate stick, it is converted into ice as soon as the former. This difference he explains in the following manner: – Some motion promotes congelation; this arises in the boiled water through its re-imbibing air; and therefore it must necessarily freeze before the unboiled, provided the latter be kept at perfect rest. Fahrenheit had before remarked that water not moved, would show a cold several degrees below the freezing-point, without becoming ice386.

M. Lichtenberg, with whom I conversed on these contradictory results, assured me that he was not surprised at this difference in the experiments. The time of congelation is regulated by circumstances, with which philosophers are not yet sufficiently acquainted. A certain, but not every degree of stirring hastens it; so that every icy particle which is formed on the side of the vessel, or which falls from the atmosphere, may convert the water sufficiently cooled into ice instantaneously; and such unavoidable accidents must, where all other circumstances are equal, cause a great difference in the period of freezing.

I am inclined to think that the cooling of water, in ancient times, of which I have already spoken, is not to be ascribed so much to the boiling as to the jars being kept continually wet, and to the air to which it was exposed. A false opinion seems therefore to have prevailed respecting the cause; and because it was considered to be the boiling, many have not mentioned the real cause, which appeared to them only to afford a trifling assistance, though it has been remarked both by Galen and Athenæus. We know at present that coolness is produced by evaporation. A thermometer kept wet in the open air falls as long as evaporation continues387. With sulphuric æther, and still better with that of nitre, which evaporates very rapidly, water may be made to freeze even in the middle of summer; and Cavallo saw in summer a Fahrenheit’s thermometer, which stood at 64°, fall in two minutes, by means of æther, to +3, that is to 29° below the freezing-point388.

On this principle depends the art of making ice at Calcutta and other parts of India, between 25° 30′ and 23° 30′ of north latitude, where natural ice is never seen unless imported. Trenches two feet deep, dug in an open plain, are strewed over with dry straw; and in these are placed small shallow unglazed earthen pans, filled with water at sunset. The ice which is produced in them is carried away before sunrise next morning, and conveyed to an ice-cellar fifteen feet deep; where it is carefully covered with straw to be preserved from the external heat and air. A great deal, in this process, depends upon the state of the atmosphere. When calm, pure and serene, it is most favourable to the congelation; but when the winds are variable, or the weather heavy and cloudy, no ice is formed; and the same is often the case when the nights are raw and cold389.

It was once believed that this freezing was occasioned principally by the water having been boiled; but it seems to be owing much rather to evaporation390. It is not however said that the vessels are kept continually wet on the outside, but that they are unglazed, and so porous or little burnt, that the water oozes through them; and on that account their exterior surface appears always moist391. By vessels of this kind the trouble of wetting is saved. What has been said respecting the influence of the weather serves, in some measure, to confirm my conjecture. The more it favours evaporation, the ice is not only formed more easily, but it is better; and when evaporation is prevented by the wind or the weather, no ice is produced. The latest accounts how ice is made at Benares, say expressly that boiled water is not employed; and that all those vessels, the pores of which are stopped by having been used, do not yield ice so soon or so good. In porcelain vessels none is produced; and this is the case also when the straw is wet392.

Another method of cooling water also seems to have been known to Plutarch. It consisted in throwing into it small pebbles or plates of lead393. The author refers to the testimony of Aristotle; but this circumstance I cannot find in the works of that philosopher which have been preserved. It seems to be too unintelligible to admit of any opinion being formed upon it; and the explanation given by Plutarch conveys still less information than the proposition itself. This is the case, in general, with almost all the propositions of the ancients. We indeed learn from the questions that they were acquainted with many phænomena; but the answers scarcely ever repay the trouble which one must employ in order to understand them. They seldom contain any further illustration; and never a satisfactory explanation.

It appears that the practice of cooling liquors, at the tables of the great, was not usual in any country besides Italy and the neighbouring states, before the end of the sixteenth century. In the middle of that century there were no ice-cellars in France; for when Bellon relates, in the Account of his travels, in 1553, how snow and ice were preserved at Constantinople throughout the whole summer, for the purpose of cooling sherbet, he assures us that the like method might be adopted by his countrymen; because he had found ice-cellars in countries warmer than France. The word glacière also is not to be met with in the older dictionaries; and it does not occur even in that of Monet, printed in 1635394. Champier, the physician who attended Francis I. when he had a conference with the emperor Charles V. and pope Paul III. at Nice, saw the Spaniards and Italians put snow, which they caused to be brought from the neighbouring mountains, into their wine in order to cool it. That practice, which excited his astonishment, he declared to be unhealthful; and this proves that in his time it had not been introduced at the French court395.

Grand d’Aussy quotes an anecdote, related by Brantome, from which he forms the same conclusion. The dauphin, son of Francis I., being accustomed to drink a great deal of water at table, even when he was overheated, Donna Agnes Beatrix Pacheco, one of the ladies of the court, by way of precaution, sent to Portugal for earthen vessels, which would render the water cooler and more healthful; and from which all the water used at the court of Portugal was drunk. As these vessels are still used in Spain and Portugal, where the wine is cooled also with snow, both methods might have been followed in France. I have in my collection of curiosities, fragments of these Portuguese vessels; they are made of red bole; are not glazed, though they are smooth, and have a faint gloss on the surface like the Etruscan vases. They are so little burnt that one can easily break them with the teeth; and the bits readily dissolve to a paste in the mouth. If water be poured into such vessels, it penetrates their substance; so that, when in the least stirred, many air-bubbles are produced; and it at length oozes entirely through them396. The water that has stood in them acquires a taste which many consider as agreeable; and it is probable that it proceeds from the bark of the fir-tree, with which, as we read, they are burnt. When the vessels are new, they perform their service better; and they must then also have a more pleasant smell. If they really render water cold, or retain it cool, that effect, in my opinion, is to be ascribed to the evaporation. Their similarity to those in which the Indians make ice is very apparent.

Towards the end of the sixteenth century, under the reign of Henry III., the use of snow must have been well known at the French court, though it appears that it was considered by the people as a mark of excessive and effeminate luxury. In the witty and severe satire on the voluptuous life of that sovereign and his favourites, known under the title of L’Isle des Hermaphrodites397, a work highly worthy of notice but which is exceedingly scarce, we find an order of the Hermaphrodites that large quantities of ice and snow should everywhere be preserved, in order that people might cool their liquors with them, even though they might occasion extraordinary maladies, which, it seems, were then apprehended. In the description of an entertainment we are told that snow and ice were placed upon the table before the king; and that he threw some of them into his wine; for the art of cooling it without weakening it was not then known. The same method was practised even during the whole first quarter of the seventeenth century398.

Towards the end of the above century this luxury must have been very common in France. At that period there were a great many who dealt in snow and ice; and this was a free trade which every person might carry on. Government, however, which could never extort from the people money enough to supply the wants of an extravagant court, farmed out, towards the end of the century, a monopoly of these cooling wares. The farmers, therefore, raised the price from time to time; but the consumption and revenue decreased so much that it was not thought worth while to continue the restriction; and the trade was again rendered free. The price immediately fell; and was never raised afterwards but by mild winters or hot summers.

The method of cooling liquors by placing them in water in which saltpetre has been dissolved, could not be known to the ancients, because they were unacquainted with that salt. They might however, have produced the same coolness by other salts which they knew, and which would have had a better effect; but this, as far as I have been able to learn, they never attempted. The above property of saltpetre was first discovered in the first half of the sixteenth century; and it was not remarked till a long period afterwards, that it belongs to other salts also.

The Italians at any rate were the first people by whom it was employed; and about the year 1550, all the water, as well as the wine, drunk at the tables of the great and rich families at Rome, was cooled in this manner. Blasius Villafranca, a Spaniard, who practised physic in that capital, and attended many of the nobility, published, in the before-mentioned year, an account of it, in which he asserts, more than once, that he was the first person who had made the discovery publicly known. In his opinion it was occasioned by the remark that salt water in summer was always cooler than fresh water. According to his directions, which are illustrated by a figure, the liquor must be put into a bottle or globular vessel with a long neck, that it may be held with more convenience; and this vessel must be immersed in another wide one filled with cold water. Saltpetre must then be thrown gradually into the water; and while it is dissolving, the bottle must be driven round with a quick motion on its axis, in one direction. Villafranca thinks that the quantity of saltpetre should be equal to a fourth or fifth part of the water; and he assures us, that when again crystallized, it may be employed several times for the same use, though this, before that period, had by many been denied. Whether other salts would not produce the like effect, the author did not think of trying; but he attempts to explain this of saltpetre from the principles of Aristotle; and he tells his noble patrons what rules they should observe for the preservation of their health, in regard to cooling liquors.

Towards the end of the sixteenth century this method of cooling liquors was well known, though no mention is made of it by Scappi, in his book on cookery. Marcus Antonius Zimara, however, speaks of it in his Problems399. I do not know at what time this Appulian physician lived. In a list of the professors of Padua, his name is to be found under the year 1525, as Explicator philosophiæ ordinariæ; and because another is named under the year 1532, we have reason to conjecture that he died about that time. But in that case the physician Villafranca would probably have been acquainted with the Problemata of Zimara; and would not have said that no one had spoken of this use of saltpetre before him.

Levinus Lemnius400 also mentions the art of cooling wine by this method so much, that the teeth can scarcely endure it. We are informed by Bayle that the earliest edition of his work, which has been often reprinted, was published at Antwerp, in the year 1559, in octavo. It contains only the first two books; but as the above account occurs in the second book, it must be found in this edition.

Nicolaus Monardes, a Spanish physician, who died about the year 1578, mentions this use of saltpetre likewise. It was invented, as he says, by the galley-slaves; but he condemns it as prejudicial to health. From some expressions which he uses, I am inclined to think that he was not sufficiently acquainted with it; and that he imagined that the salt itself was put into the liquor. At a later period we find some account of it in various books of receipts; such as that written by Mizaldus in 1566, and which was printed for the first time the year following401.

In the Mineralogy of Aldrovandi, first printed in 1648, this process is described after Villafranca; but where the editor, Bartholomæus Ambrosianus, speaks of common salt, he relates that it was usual in countries where fresh water was scarce to make deep pits in the earth; to throw rock-salt into them; and to place in them vessels filled with water, in order that it might be cooled. This remark proves that the latter salt was then employed for the same purpose; but it has led the editor into a very gross error. He thinks he can conclude from it, that the intention of potters, when they mix common salt with their clay, is not only to render the vessel more compact, but also to make it more cooling for liquors. But the former only is true. The addition of salt produces in clay, otherwise difficult to be fused, the faintest commencement of vitrification; a cohesion by which the vessel becomes so solid that it can contain fluids, even when unglazed; but for this very reason it would be most improper for cooling, which is promoted by the evaporation of the water that oozes through.

The Jesuit Cabeus, who wrote a voluminous commentary on the Meteorologica of Aristotle, which were printed at Rome in 1646, assures us that with thirty-five pounds of saltpetre one can not only cool a hundred pounds of water, by quickly stirring it, but convert it also into solid ice; and for the truth of this assertion he refers to an experiment which he made. Bartholin says that for the above account he can give him full credit402; but the truth of it is denied by Duhamel, who suspects that this Jesuit took the shooting crystals of the salt to be ice403.

Who first conceived the idea of mixing snow or ice with saltpetre and other salts, which increases the cold so much, that a vessel filled with water, placed in that mixture, is congealed into a solid mass of ice that may be used on the table, I cannot with certainty determine; but I shall mention the earliest account of it that I have been able to find. Latinus Tancredus, a physician and professor at Naples, whose book De Fame et Siti was published in 1607, speaks of this experiment; and assures us that the cold was so much strengthened by saltpetre, that a glass filled with water, when quickly moved in the above mixture, became solid ice404.

In the year 1626, the well-known commentary on the works of Avicenna, by Sanct. Sanctorius, was published at Venice. The author in this work relates, that in the presence of many spectators, he had converted wine into ice, not by a mixture of snow and saltpetre, but of snow and common salt405. When the salt was equal to a third part of the snow, the cold was three times as strong as when snow was used alone.

Lord Bacon, who died in 1626, says that a new method had been found out of bringing snow and ice to such a degree of cold, by means of saltpetre, as to make water freeze. This, he tells us, can be done also with common salt; by which it is probable he meant unpurified rock-salt; and, he adds, that in warm countries, where snow was not to be found, people made ice with saltpetre alone; but that he himself had never tried the experiment406. Boyle, who died in 1691, made experiments with various kinds of salts; and he describes how, by means of salt, a piece of ice may be frozen to another solid body407. Descartes says that in his time this was a well-known phænomenon, but highly worthy of attention408.

Since that period the art of making ice has been spoken of in the writings of all philosophers where they treated on heat and cold, and with many other experiments has been introduced into various books of receipts. It was then employed merely for amusement409; and no one suspected that it would ever form an important item of luxury. In the like manner Fugger’s first bills of exchange were said to be useful only for gambling, and gunpowder was called a trifling discovery.

In the beginning of the seventeenth century, drinking-cups made of ice and iced fruit were first brought to the table; but towards the end of that century it appears that the French began to congeal in this manner all kinds of well-tasted juices, which were served up as refreshments at the tables of the great and wealthy410. This was a grand invention for the art of cookery; which became common among the German cooks, both male and female, about the middle of the last century; and since that time our confectioners sell single glasses of iced articles at balls and in the theatres.

I am acquainted with no older information respecting this invention than what is contained in Barclay’s Argenis, which is, indeed, a romance; but the author’s account makes the possibility of its being used so clear, that we may certainly conclude it was then employed; especially as he mentions it several times. Arsidas finds in the middle of summer, at the table of Juba, fresh apples, one-half of which was encrusted with transparent ice. A basin, made also of ice and filled with wine, was handed to him; and he was informed that to prepare all these things in summer was a new art. Snow was preserved throughout the whole year in pits lined with straw. Two cups made of copper were placed the one within the other, so as to leave a small space between them, which was filled with water; the cups were then put into a pail, amidst a mixture of snow and unpurified salt coarsely pounded, and the water in three hours was converted into a cup of solid ice, as well-formed as if it had come from the hands of a pewterer. In the like manner apples just pulled from the tree were covered with a coat of ice.

The first edition of the Argenis was printed at Paris in 1621, and in that year the author died at the age of thirty-nine.

After brandy, from being a medicine, came into general use as a liquor at table, and was drunk in common by the populace, the Italians, above all, endeavoured to render it weaker and more pleasant by various mixtures; and by raising its value to make it more respectable, and at the same time more useful to people of the first rank. That their wares might be distinguished with more certainty, they gave them the name of liquori; and under that appellation sold them to foreign nations. The French were the first who adopted the use of these articles; particularly after the marriage of Henry II., when duke of Orleans, with Catharine de Medici, in the year 1533. This event brought to France great numbers of Italians, who made the French acquainted with these delicacies of their native country; and who taught them to prepare and to use them. They were the first, therefore, who made and sold the fine liqueurs at Paris; and in order to serve those who could not bear heating liquors, or rather to serve themselves by filling their pockets with money, their successors in this business invented about the year 1630 or 1633 that beverage called lemonade, because the juice of lemons or oranges was its chief component part. This liquor soon came into high repute, as it not only served for cooling and refreshing people during the sultry heats of summer, but was even recommended by physicians against putrid diseases.

The limonadiers, or venders of lemonade, endeavoured to increase the first property, which occasioned the far greatest consumption, by the means of ice; and one of them, Procope Couteaux, an Italian from Florence, about the year 1660, conceived the happy idea of converting such beverage entirely into ice, by a process which had been before employed only by jugglers. The ready sale which he found for his invention induced others to make articles of the like kind. His example, therefore, was followed by Le Fevre and Foi; and these three for some years enjoyed a monopoly of this new-fashioned commodity. About the year 1676, liquors cooled by, or changed into ice, must however have been the principal things sold by the limonadiers; for being then formed into a company, the following delicacies were mentioned in the patent which they received on that occasion: “Eaux de gelée et glaces de fruits et de fleurs, d’anis et de canelle, franchipanne, d’aigre de cetre, du sorbec,” &c. There were at that time in Paris two hundred and fifty masters in this employment. In 1690, when De la Quintiny wrote, iced liquors were extremely common411.

People, however, long imagined that such articles could be used only during the hot months of summer. In the year 1750, Dubuisson, successor to the celebrated Procope, au café de la rue des Fossés de S. Germain des Près, and author of the Art du Déstillateur, began to keep ready prepared, the whole year through, ices of every kind for the use of those who were fond of them. At first they were little called for, except in the dog-days; but some physicians recommended them in certain disorders. Have the physicians then, by their opinion, done most service to the venders of liqueurs and to cooks, or the latter to the physicians? This would make a fine subject for an inaugural dissertation. It is, however, certain, for we are told so by Dubuisson himself, that after two cures, in which ices had been of the greatest service, the more discerning part of the public made use of them in every season of the year. That this part of the public might never lose their conceit, the venders of liqueurs always employed their thoughts upon new inventions. Among the latest is that of iced butter, which acquired its name on account of some likeness to that substance. It was first known at the Parisian coffee-house (caveau) in 1774. The Duke de Chartres often went thither to enjoy a glass of iced liquor; and the landlord, to his great satisfaction and surprise, having one day presented him with his arms formed of eatable ice, articles of a similar kind immediately became fashionable.

[Ice is now used extensively for a variety of œconomical purposes, such as packing salmon, cooling liquors, &c. Of late years it has become a regular article of commerce. In September 1833, a cargo of ice, shipped at Boston, was discharged at Calcutta. It was sold at threepence per pound, while the native ice fetched sixpence. It was packed in solid masses, within chambers of double planking, with a layer of refuse tan or bark between them. The quantity shipped was 180 tons, of which about 60 wasted on the voyage, and 20 on the passage up the river to Calcutta. Thousands of tons are now annually shipped from Boston (United States) to our East Indies, to the West Indian Archipelago, and to the Continent of South America, and quite recently ‘The Wenham Lake Ice Company’ have erected extensive ice-houses in London and at Liverpool, and arranged for the transportation to this country of thousands of tons of ice. One surprising circumstance connected with the trade, is the fact that their ice, though transported to this country in the heat of summer, is scarcely reduced in bulk. The masses are so large that they expose a very small surface to atmospheric action in proportion to their weight, and therefore do not suffer from exposure to it, as the smaller and thinner fragments do, which are obtained in our own or other warmer climates. It appears, also, that ice frozen upon very deep water, is more hard and solid than ice of the same thickness obtained from shallow water; and even when an equal surface is exposed, melts more slowly. In this country, the collection of ice, even by those largely engaged in the trade, is an occasional and fitful undertaking; depending, both as to time and quantity, upon the accidental occurrence of severe frost; and when the process of collection is carried on, it is with very few artificial aids. In America, on the other hand, this labour can be regularly carried on through the whole winter; while the adjuncts of machinery for cutting and storing, and of steam for transporting it, are brought extensively into action.

The details connected with this trade, as carried on in America, are so novel and so interesting, that we lay them before our readers with the confident belief that the result of our labours will prove attractive to them. Wenham Lake, whence a large proportion of the ice now imported to this country is obtained, is eighteen miles from Boston, in the State of Massachusets; it occupies a very elevated position, and lies embosomed in hills of majestic height and bold rugged character. The lake has no inlet whatever, but is fed solely by the springs which issue from the rocks at its bottom, a depth of 200 feet from its surface. The ice-house, which is capable of storing 20,000 tons of ice, is built of wood, with double walls, two feet apart, all around; the space between which is filled with sawdust; thus interposing a medium, that is a non-conductor of heat, between the ice and the external air; the consequence of which is, that the ice is scarcely affected by any condition or temperature of the external atmosphere, and can be preserved without waste for an indefinite time.

The machinery employed for cutting the ice is very curious, and was invented for that express purpose. It is worked by men and horses in the following manner: – From the time when the ice first forms, it is carefully kept free from snow until it is thick enough to be cut; that process commences when the ice is a foot thick. A surface of some two acres is then selected, which at that thickness will furnish about 2000 tons, and a straight line is then drawn through its centre from side to side each way. A small hand-plough is pushed along one of these lines, until the groove is about three inches deep and a quarter of an inch in width, when the ‘Marker’ is introduced. This implement is drawn by two horses, and makes two new grooves, parallel with the first, twenty-one inches apart; the gauge remaining in the original groove. The marker is then shifted to the outside groove, and makes two more. Having drawn these lines over the whole surface in one direction, the same process is repeated in a transverse direction, marking all the ice out into squares of 21 inches. In the meantime, the ‘Plough,’ drawn by a single horse, is following in these grooves, cutting the ice to a depth of 6 inches. One entire range of blocks is then sawn out, and the remainder are split off toward the opening thus made with an iron bar. This bar is shaped like a spade and of a wedge-like form. When it is dropped into the groove, the block splits off; a very slight blow being sufficient to produce that effect, especially in very cold weather. The labour of ‘splitting’ is slight or otherwise, according to the temperature of the atmosphere. ‘Platforms,’ or low tables of frame-work, are placed near the opening made in the ice, with iron slides extending into the water, and a man stands on each side of this slide, armed with an ice-hook. With this hook the ice is caught and by a sudden jerk thrown up the ‘slide’ on to the ‘platform.’ In a cold day everything is speedily covered with ice by the freezing of the water on the platforms, slides, &c., and the enormous blocks of ice, weighing some of them more than two cwt., are hurled along these slippery surfaces, as if they were without weight. Beside this platform, stands a ‘sled’ of the same height, capable of containing about three tons; which, when loaded, is drawn upon the ice to the front of the store-house, where a large stationary platform of exactly the same height, is ready to receive its load; which, as soon as discharged, is hoisted block by block, into the house.

Forty men and twelve horses will cut and stow away 400 tons a day. In favourable weather 100 men are sometimes employed at once. When a thaw or a fall of rain occurs, it entirely unfits the ice for market, by rendering it opake and porous; and occasionally snow is immediately followed by rain, and that again by frost, forming snow-ice, which is valueless, and must be removed by the ‘plane.’ The operation of ‘planing’ is somewhat similar to that of ‘cutting.’ A plane gauged to run in the grooves made by the ‘marker,’ and which shaves the ice to the depth of three inches, is drawn by a horse, until the whole surface of the ice is planed. The chips thus produced are then scraped off; and if the clear ice is not reached, the process is repeated. If this makes the ice too thin for cutting, it is left in statu quo