« 이전계속 »
and'the capitals of the pillars are entirely rounded away, and even St. Anthony himself, a very tolerable statue considering the artist and the materials, has been almost deprived of his nose, the most unseemly of all failings in canonized sanctity. In fact, Wieliczka has been the subjectof much exaggeration. It is not true thai the miners have their houses and villages beneath ground, that some of them have been born there, and that still more of them have never been on earth since they first descended; for, though the labour is carried on without" interruption during the four-and-twenty hours, the workmen here, as in most other mines, are divided into three hands, each of which works only eight hours, and their houses, wives, and families are above ground. It is true that the horses employed in removing the barrels of saltfrom different parts of the mine to the mouth of the shaft, through which they are drawn up, rarely revisit daylight after they have once descended, and that they have their stables and hay lofts below ground; but it is not true that they generally become blind from living so much in the dark. The often repeated wonder of a stream of fresh water flowing through the salt rock is equally void of foundation; but neither is it true that all the fresh water in the mine is brought down artificially from above. There are some springs of fresh water, but there is no reason to suppose they even touch the salt rock. In Wieliczka the wood used in the mine is as hard as rock. I was assured that even animals which die there do not putrify, but merely assume the appearance of stuffed birds and beasts; and it was added, that when, in 1696, the bodies of some workmen who, it was supposed, had perished in the great conflagration, were found in a retired and deserted corner of the mine, they were as dry and hard as mummies.
"Tn the deeper galleries the operations have been carried on with much greater care and regu
larity. In them the salt assumes more decidedly the character of a continuous stratum, although it is often interrupted, both vertically and horizontally, by veins of rock. The saltis cut out from long narrow blocks, as if from a quarry; it is then broken into smaller pieces and packed up in barrels, At certain distances masses of it are left standing to act as pillars in supporting the roof. Its colour, in the mass, is dark, nor is the reflection of light from its surface at all so dazzling as has sometimes been represented. When, indeed, flambeaux are flashing from every point of the rock, and the galleries and caverns are illuminated, as they sometimes have- been in honour of royal personages, then crystallized walls and ceilings may throw back a flood of light, but in their ordinary state, illuminated only with the small lights, by the guidance of which the miners persue their labours,. the effect is neither very brilliant nor imposing.
PREPARATION OF BORAX IN PERSIA.
Crell's Annalen for 1791, describes this as follows:—The water of an alkaline spring, which is hardly an inch in diameter, is collected in marble basins, and thence is conveyed into untinned copper kettles, where it is mixed with blood, urine, and scrapings of leather, and allowed to putrify for five or six weeks. The deposit at the bottom of the kettle is then boiled with water, and on cooling, a rude but not crystallized species of borax, called by the Persians bora, is obtained.
FORMATION OF AMMONIA. M. Chevallier has informed the Institute of France, that during the oxidation of iron by the contact of air and water, ammonia is formed ; which seems to show, that the metal takes oxygen both from the air and the water, while the two other principles of these two compounds, viz. azote and hydrogen, unite and form ammonia.
TO MAKE WATER-SPOUTS. Mr. Editor,—As you were so obliging as to insert my late communication immediately, I herewith send you another. The following is the manner in which the boys of my country, who, you know, are 'very studious and philosophical, make water-spouts.— Take a piece of fresh burnt lime, and throw it, while it is hot, into water; when it has fallen to powder, stir it about, and pour the whole into a cylindrical glass vessel, with a cork, as at d. Thrust a thin iron wire through the cork, and bend it both above and below at right angles. It is not to descend quite to the middle of the vessel. On turning the wire ro»ind by means of the upper part, e, the under part also describes a circle in the water as seen at b c, and gives the water a similar motion. After a little the lime at the bottom begins to move; if it has been well settled,, and the wire is not turned round too quick, the lime gathers itself into a heap immediately under the wire, and a small round column arises to the top. . If the motion of the wire be continued, part of the lime falls again to the bottom, and winds round the centre column something like a corkscrew, as seen in the little drawing I send you ; or rather like a hollow pillar with a descending spiral thread around it. In the centre there appears to arise a finer dust in a spiral form,
till it reaches the wire at a, when it spreads itself out in two horizontal branches, and has the appearance of four distinct whirlpools, two of each moving in different directions. Below, the column appears to have only one base, as at /, which almost immediately branches off into two, as at g and h. The whole column waves backwards and forwards, precisely as travellers'describe water-spouts to do, and, like them, it spreads itself out under the top of the glass, as they spread themselves into -the clouds. Your former Correspondent,
SUBNITRATE OF BISMUTH,
A Substance now for the first time introduced in the Pharmacopoeia, and said to possess great antispasmodic powers, and to be especially serviceable in those forms of dyspepsia which are attended with painful contractions of the stomach. To prepare it, take of bismuth an ounce, nitric acid a fluid ounce and a half, distilled water three pints; mix six fluid drachms of the distilled water with the nitric acid, and dissolve the bismuth in the mixture; then filter the solution, add the remainder of the water to the filtered fluid, and set it by, that the powder may subside. Lastly, having poured off the supernatant fluid, wash the submuriate of bismuth with distilled water, and dry it, wrapped in bibulous paper, with a gentle heat.
TO BREATHE FIRE.
Isolate electrically a large shallow dish, and then electrify the water strongly. If while this is going on, a person, having wetted his mouth, breathes towards the water, standing about a foot from it, he will to the spectators have the appearance of breathing fire, and may, if he be so disposed, play thedovilZamiel,in the Freyschutz, or persuade the credulous that he is a magician. s
is so striking, that it must have very early attracted attention. To direct this power by making steam flow through pipes or apertures, is the first and most obvious method of employing steam. Steam only requires to bo sufficiently cooled to be again condensed into water, thenoccupying between 18 and 19 hundred times less space than when it existed as steam. Wherever this condensation takes place, the atmosphere has a tendency proportioned to its own weight, to rush in and supply the vacancy left by the water occupying so much smaller a space than the steam. The weight of the atmosphere, therefore, forcing it into the place left vacant, is the second mode in which steam may be employed in producing power. The effects of both these modes may be united, and applied in different manners, and directed to various objects. The former is the more obvious and simple; the latter, even if discovered ever so early, could scarcely have been put to any good practical purpose, without that general knowledge of the atmosphere, which was not acquired till the 17th century. It was the former, therefore, which was first employed, and the various adaptations which it underwent, employing the second mode by itself and uniting it with the other; and their different adaptations, each of which has had one or more inventors, have given rise to a number of conflicting claims for the honour of havinginvented the whole steam-engine. By shortly tracing the progress of this invention, we shall show that, like every discovery of great benefit to the human race, it was not the production of one person, but of the general knowledge of society.
The first person of whom any notice is preserved as having employed steam as a moving power, was Hero the elder, a Greek, who flourished about 130 years before the Christian era. The mode in ■which he generated motion by steam is not, however, the most simple. By making steam pass out of two opposite tubes of
a hollow globe suspended on two pivots, the end of each tube being bent horizontally, the globe receives, by the resistance the steam meets on passing into the atmosphere, a whirling motion, which is continued as long as the steam is generated. From that time to 1002 we find no notice of steam as a moving power. Under this date, however, (ssiys the Editor of the Mechanic's Magazine) we find, in William of Malmesbury's History, mention is made of "an hydraulic organ at Rheims, in which the air, escaping in a surprising manner, by the force of heated water, fills the cavity of the instrument, and the brazen pipes emit modulated tones." In 1536, the next time steam-engines are known to be alluded to, one Mathesius; in a volume of sermons, entitled "Sarpeta," hints at the possibility of constructing an apparatus similar to a steam-engine. Thirty years afterwards, a whirling oclipile was described in a book printed at Leipsic. It is the same as Hero's machine, and was probably copied from his description. It is recommended, however, by the moderns, as exceedingly well adapted to the purpose of turning the spit for the cook; it eats nothing, and gives withal an assarance to those partaking of the feast, that the haunch has not been pawed by the turnspit for the pleasure of licking his unclean fingers. In 1615, Solomon de Caus published a book, in which an engine for forcing up water by the elasticity of steam is described. This was said to be effected by heating water in a vessel provided with two tubes, one of which was for the admission of water, and the other, which descended nearly to the bottom, was for the emission. When the water was heated, the expansion of the vapour on the surface of the water forced it up the tube at the bottom of the vessel. .;
Giovanni Branca, an Italian mathematician, who resided at Rome in the beginning of the 17th century, directed a stream or jet of steam, issuing from a narrow aperlure, on a wheel formed with float' boards, and revolving on its axis, like a water-wheel. The steam operated so powerfully on it that it was employed l>y some intermediate mechanism to give motion to the stampers of a mill for pounding drugs. After this period the power of the elasticity of steam to raise water was employed in a variety of modes by watet-work artists, Who were then much in vogue; but none of them seem to have had much influence in promoting the further use and improvement of the .steam-engine. From a passage in Bishop Wilkins's Mathematical Magic, published in 1648, there is some reason to believe Branca's mode of supplying steam was then known and practised in England. In that famous book called the Century of Inventions, published in 1663, the Marquis of Worcester claims for himself the honour of having invented an admirable and forcible way of drawing up water by fire. Nobody has, however, been able to make a machine from the marquis's description. Mr. Stuart is rather inclined to treat this gentleman as having been somewhat of a quack, and, considering what he has borrowed from others, to have no claim to the honour often bestowed on him, of having invented the steam-engine. In 1682, Sir Samuel Morland had a scheme for raising water by the force of steam; but no description of his apparatus or its principle is known to be in existence. He was the author, however, of some experiments on the expansive power of steam, which must have been made with considerable care. Dr. Denis Papin, the undoubted inventor of a digester bearing his name, and of safety valves, seems to have been the first person who thought of creating a vacuum by the means of condensing steam, and employing that as a moving power. This thought, though thrown out in 1695, was not carried into execution; and in 1702, Captain Savary, a seafaring gentleman, introduced, in a work called the Miners'Friend,
his engine to public notice. Of this engine, which was undoubtedly the first steam-engine, properly so called, we shall, by the permission or Mr. Stuart, present our readers with a representation, and a detailed description:—
"The first thing," says, the ingenious inventor, " is to fix the engine In a good double furnace, so contrived that the flame of your fire may circulate round, and encompass your two boilers, as you do coppers for brewing. Before you make any fire, unscrew G and N, being the two small gauge ■pipes and cocks belonging to the two boilers, and at the holes fill LL, the great boiler, two-thirds full of water, and D, the small boiler, quite full; then screw in the said pipes again as fast and as tight as possible. Then light the fire at b, and when the water in L boils, the handle of the regulator, marked Z, must be thrust from you as far as it will go, which makes all the steam rising- from the water in L pass with irresistible force through O into _P, pushing out all the air before it through the clack r, making a noise as it goes; and when all is gone out, the bottom of the vessel, P, will be very hot. Then pull the handle of the regulator to you, by which means you stop O, and force your steam through Oo into Ps, until that vessel has discharged its air through the clack, R, up the forcepipe, S. In the mean time, by the steam's condensing in the vessel, P, a vacuum or emptiness is created, so that the water must and will necessarily rise up through the sucking-pipe, T, lifting up the clack, M, and filling the vessel, P.
"In the mean tigie, the vessel, P/», being emptied of its air, turn the handle of the regulator from you again, and the force is upon the surface of the water in p; which surface being only heated by the steam, it does not condense it, but the steam gravitates or presses with an elastic quality like air, still increasing its elasticity or spring till it counterpoises or rather exceeds the weight of the water ascending in S, the forcing-pipe, out of which the water in it will be immediately discharged when once gotten to the top, which takes up so; e time to recover that power; which having once got, and being in work, it is easy lor any one that never saw the engine, after half an hour's experience, to keep a constant stream running out the full bore of the pipe. On the out