phurick acid diluted with an equal weight of water: by the action of a gentle heat the gas will be given off. It may also be obtained by the action of muriatick acid upon the same oxide. Cold water dissolves about twice its volume of chlorine; and mercury rapidly combines with it. It is best collected over warm water; and the waste from absorption may be diminished by leading the pipe, by which it is conducted, to the top of the jar; as was before recommended for the protoxide of nitrogen. It may be preserved in bottles with glass stoppers well greased, taking care that the water is wholly expelled from them. It possesses a yellowish green colour, an astringent taste, and a most suffocating smell; all of which qualities are communicated to its aqueous solution. If received into the lungs, its action is extremely Water thus combined with a salt is called its water of crystallization: it is essential to its exist-painful and injurious. ence in the crystalline state, but may be generally expelled by heat, leaving the anhydrous salt in an amorphous (or shapeless) state, but with all its properties unchanged. This it is difficult to effect in the present instance, as the salt is very easily decomposed by heat, and at a temperature of 600 explodes, being wholly resolved into its elements. It is considerably heavier than common air: 100 cubick inches weigh 76.3 grains. When a burning taper is introduced into it, it is quickly consumed with a dull red flame, which throws off a dense black smoke: phosphorus spontaneously ignites in it, and burns with a pale white flame; and several of the metals, in a finely-divided state, or in thin leaves, inflame: and in this way tin, copper, and The results of its decomposition at a lower temper-zinc, exhibit a beautiful appearance. ature we have already shown, in describing the formation of the protoxide of nitrogen; and this process may now be understood. Nitrate of ammonia, which is melted at a gentle heat, is composed of 1 equivalent nitrick acid, 54 1 equivalent ammo nia, 17 1 equ. nitrogen, 14 Chlorine mixed with the vapour of water, as it is usually obtained, assumes the liquid form at a temperature of 40°; and when surrounded with snow or pounded ice, concretes into a solid of a yellowish colour; which is deposited upon the sides of the receiver, like the effects of frost upon the surface of windows. If the gas be artificially dried by passing it over substances which abstract vapour, as a salt known by the name of muriate of lime, the most in- . tense artificial cold produces no effect upon it. Strong compression, equal to four atmospheres, will, however, reduce it to the liquid form. It has no acid properties it is not sour, and it does not change the blue colour of vegetables to red; but it destroys all animal and vegetable colours, and is a most important agent In this decomposition the 3 proportions of hydro- in the art of bleaching. This, however, it can only gen take 3 of oxygen, and form water; and the re-effect when water is present. If a piece of dry litmaining 2 proportions of oxygen combine with the 2 of nitrogen, and produce the protoxide of nitrogen: and these are the only products. or, in other words, the salt is composed of 3 do. hydrogen, 3 28 3 40 2 equivalents nitrogen 3 do. hydrogen 5 do. oxygen mus paper be introduced into a jar of dry chlorine, it will suffer no change; but if previously wetted, the colour will speedily disappear. The colours of printed calico may readily be discharged by the same It is almost impossible for the least contemplative mind not to be struck with admiration at the harmo-means. nious simplicity of the laws upon which these transmutations depend: and the feeling of satisfaction which their developement produces is part of that pure delight which, independently of more substantial advantages, rewards the diligent student of the works of nature. ON CHLORINE.* CHLORINE AND HYDROGEN. the Muriatick Acid. Chlorine and hydrogen may mixed together; and if carefully excluded from the light of day, will remain without change. mixture be made with equal volumes of the two and exposed to light, they will gradually combine; the chlorine will lose its peculiar cour and smell, and a Chlorine, the last of the four aeriform elements powerfully acid gas will result, without any change which we have enumerated, belongs, with oxygen, to of volume. If the mixture be made in a stout phial, the electro-negative class; being evolved from all its with a well-fitted stopper, secured by wrapping a compositions, except with oxygen, at the positive pole cloth round the neck, and exposed to the direct rays of the Voltaick pile. It may be obtained as follows: of the sun, the combination will take place suddenly Mix three parts of sea-salt finely pounded with one and with detonation. When the stopper is afterwards of peroxide of manganese-a substance well known withdrawn under mercury, it will be found that no in several of the arts by the name of black manga-condensation has taken place; but if under water, it nese; pour upon them in a retort two parts of sul-will instantly rush in and fill the phial-as the new compound is rapidly absorbed by that liquid. The * From a Greek word, signifying "green," from its colour. which agrees very nearly with direct experiment. Muriatick acid gas is best obtained by the action of strong sulphurick acid upon an equal weight of sea salt it is given off in great purity, but must be collected over mercury. The properties of such gases as are rapidly absorbed by water, may be examined without a regular mercurial apparatus, by means of a glass tube from half to three quarters of an inch diameter, and from four to ten inches in length. It is closed above, but open at the lower extremity, and turned up. It may be filled with mercury, and is then to be supported with a saucer beneath it. The soluble gas may be produced in a small tube, or retort, drawn out, and fixed in such a way that the end may be introduced at the mouth so far as to allow the bubbles to pass into the tube, and the mercury to flow out into the saucer. When the metal has descended nearly to the bend, the operation should be stopped. Small portions of the gas so collected, may afterwards be examined, by placing the finger upon the aperture in contact with the mercury, so as to exclude all air. By inclining the tube, a bubble of the gas may be made to pass round the bend towards the finger; and upon replacing the tube in the perpendicular position, the larger quantity will still be in the upright part, and a small quantity confined between the mercury and the finger, and quite unconnected with the former. This quantity may thus be conveniently experimented upon. Muriatick acid gas is colourless, of a very pungent smell, and intensely acid taste. have but a feeble affinity for each other; but four distinct compounds of the two elements may be obtained by indirect means. They are never found in nature, and are subjects of instruction and curiosity rather than of use in the arts. There is a salt to which we have before referred, and the formation of which will be hereafter described, known by the name of chlorate of potash: when this salt is heated in a retort, with very weak muriatick acid, a gas may be collected over mercury: but as it is very apt to explode, the application of a naked flame to the retort should be avoided, and the heat is best applied by the medium of water. It differs very materially from chlorine. Its colour is much deeper, and is of a brighter yellow tint: its smell is intermediate between that of burnt sugar and chlorine. It explodes by the application of a very gentle heat, not exceeding that of the hand, and is decomposed. Five volumes become expanded to 6, consisting of a mixture of chlorine and oxygen, in the proportions of 4 of the former to two of the latter; the oxygen in the compound being condensed into half its bulk. These proportions prove that it is a compound by weight of Its attraction for water is so great, that when a It extinguishes flame and is incombustible. A has been reduced to a liquid state by a pressure It may be mixed with hydrogen, and exploded by the electrick spark, and muriatick acid and water are the products. Peroxide of Chlorine. Another combination of chlorine and oxygen may be obtained by operating a at the temperature of 40°, will absorb of upon chlorate of potash with sulphurick acid: 50 or it about 480 mes its volume, and thereby increases 60 grains of the salt in powder may be mixed with its bulk. The sution is commonly known by the strong sulphurick acid into a paste. The mixture name of muriatick acic, and is largely employed for will assume a bright orange colour. chymical purposes. It may be prepared by passing placed in a small retort, or bent tube, which should It may be the gas, produced as above, immediately into water; be immersed in water, and gently heated, taking or by adding a sufficiency of water to the sulphurick care to keep it under 212°, or the boiling point. A acid in the first instance, and then distilling. The gas will be given off, which may be received over solution, when pure, is perfectly colourless, and it mercury, on which it has no action at common tempossesses all the acid properties and smell of the gas. perature. Its specifick gravity is greater than that of water, and when it amounts to 1.920 (water being considered the protoxide, and it is still more rapidly absorbed by Its colour is also yellow, but brighter than that of 1.00) 100 parts contain 28.3 of real acid. water. The solution is deep yellow, and its taste not It may be called the peroxide of chlorine. Phosphorus spontaneously ignites in it, and causes it to explode. Chlorick acid. The combination of chlorine with a further proportion of oxygen constitutes an acid, which may be obtained by decomposing a salt, which will be hereafter described, called chlorate of barytes, by elective affinity with dilute sulphurick acid. Great care must be taken not to use an excess of sulphurick acid; which may be dropped into a solution of the chlorate in water, as long as any white precipitate appears. The clear liquor which remains, after the process is complete, should be cleansed from the sediment; it consists of a solution of chlorick acid in water. It may be concentrated by careful evaporation till it acquires an oily consistency. upon in quantities larger than a grain of mustardseed; and even then it should be handled with extreme caution. Its specifick gravity is 1.653, and it does not become solid at great degrees of artificial cold. At a temperature of about 200° it explodes; but the mere contact of some combustible substances, at ordinary temperatures, causes it to detonate. When a globule is thrown into olive oil, or turpentine, it explodes so violently as to shatter any glass vessel. The products of its decomposition are chlorine and nitrogen, and its composition has been inferred to be The name of chloride of nitrogen has been given to it: the chymical nomenclature conferring the appellation of chloride upon the combinations of chlorine with all bodies except oxygen, which have not acid properties: and as the analogous compounds of oxygen, when in more than one propo..ion, are distinguished by prefixing the Greek numerals, so the chlorides of different proportions are called protochloride, deuto-chloride, &c. NATURAL HISTORY. METHOD OF CAPTURING WILD DUCKS. It is colourless; its taste acid and astringent; and its smell, when warmed, pungent. It reddens the colour of blue vegetables. The chlorick and muri- The decoys used in England, particularly in the atick acids decompose each other, and, if mixed in fens of Lincolnshire are superiour to any method of proper proportions, they are each resolved into chlo-catching wild ducks with which we are acquainted. rine by the union of the oxygen and hydrogen, with A circumstantial account of this process is given by which they are severally combined. Chlorick acid Bewick, and illustrated by our wood cut. is composed of In the lakes to which the wild ducks resort, their most favourite haunts are observed. Then in the most sequestered part of this haunt, a ditch is cut, which is about four yards across at the entrance, and decreases gradually in width from the entrance to the farther end, which is not more than two feet wide. The ditch is of a circular form, but does not bend much for the first ten yards. The banks of the lake on each side of this ditch (or "pipe," as it is called) are kept clear from reeds, coarse herbage, &c., in order that the fowl may get on them to sit and dress themselves. Along the ditch poles are driven into the ground, close to its edge, on each side, and the tops are bent over across the ditch and tied together. These poles, thus bent, form at the entrance of the ditch or pipe an arch, the top of which is ten feet distant from the surface of the water. This arch is made to decrease in height as the pipe decreases in width, so that the remote end is not more than eighteen inches in height. The poles are placed about six feet from each other, and conrected by poles laid lengthwise across the arch and tied together. Over the whole is thrown a net, which is made fast to a reed-fence at the entrance and nine or ten yards up the ditch, and afterwards strongly pegged to the ground. At the end of the pipe farthest from the entrance is fixed a "tunnel-net," as it is called, about four yards in length, of a round form, and kept open by a number of hoops, about eighteen inches in diameter, placed at a small distance from each other to keep it distended. Supposing the circular bend of the pipe to be to the right when one stands with his back to the lake, then on the left hand side a number of reed-fences are constructed, called "shootings," for the purpose of screening the "decoy-man" from observation, and in such a manner that the fowl in the decoy may not be alarmed while he is driving those that are in the pipe. These shootings, which are ten in number, are about four yards in length, and about six feet high. From the end of the last shooting a person cannot see the lake, owing to the bend of the pipes, and there is then no further occasion for shelter. Were it not for these shootings, the fowl that remain about the mouth of the pipe would be alarmed if the person driving the fowl already under the net should be exposed, and would become so shy as entirely to forsake the place. The first thing the decoy-man does when he approaches the pipe is to take a piece of lighted turf, or peat, and hold it near his mouth, to prevent the birds from smelling him. He is attended by a dog, trained for the purpose of rendering him assistance. He walks very silently about half-way up the shootings, where a small piece of wood is thrust through the reed-fence, which makes an aperture just large enough to enable him to see if any fowl are in; if not, he walks forward to see if any are about the entrance of the pipe. If there are, he stops and makes a motion to his dog, and gives him a piece of cheese, or something else, to eat; and, having received this, the animal goes directly to a hole through the reed-fence, and the birds immediately fly off the bank into the water. The dog returns along the bank between the reed-fences, and comes out to his master at another hole. The man then gives him something to reward and encourage him, and the animal repeats his round until the birds are attracted by his motions, and follow him into the mouth of the pipe. This operation is called "working" them. The man now retreats farther back, working the dog at different holes until the ducks are sufficiently under the net. He then commands his dog to lie down behind the fence, and going himself forward to the end of the pipe next the lake, he takes off his hat and gives it a wave between the shooting. All the birds that are under the net can then see him; but none that are in the lake can. The former fly forward, and the man then runs to the next shooting and waves his hat, and so on, driving them along until they come to the tunnel-net, into which they creep. When they are all in, the man gives the net a twist, so as to prevent them from getting back. He then takes the net off from the end of the pipe, and taking out, one by one, the ducks that are in it, dislocates their necks. The net is afterwards hung on again for the repetition of the process; and in this manner five or six dozen have sometimes been taken at one drift. When the wind blows directly in or out of the pipes the fowl seldom work well, especially when it blows into the pipe. The reason of this is, that the ducks always prefer swimming against the wind, otherwise the wind blow. ing from behind catches and ruffles their feathers. If many pipes are made in the same lake, they are so constructed as to suit different winds and are worked accordingly. The better to entice the fowl into the pipe, hemp-seed is occasionally strewn on the water. The season allowed by Act of Parliament for taking ducks in this way is from the latter end of October until February. Willughby states that formerly before the young ducks took flight, or while the old ones were in moult and unable to fly, they were driven by men in boats furnished with long poles, with which they splashed the water, between long nets stretched vertically across the pools in the shape of two sides of a triangle, into lesser nets placed at the point, and in this way he says that 4000 were taken at one drive in Deeping Fen; and Latham has recorded an instance in which 2646 were taken in two days near Spalding, in Lincolnshire; but these practices being considered injurious, were prohibited by statute in the reign of George II. Tame ducks are also used for the purpose of leading the way into the pipe. Hence the term " decoyducks." These birds are fed on the pond, and made quite tame, and come to the keeper's whistle, to eat the hemp-seed which he strews on the pond. They generally lead the way into the pipe when whistled to. which resounds as if a large stone had fallen into it, and recovers its smoothness before the bird re As they are used to the sight of the keeper, they do head-foremost, with prodigious velocity into the water, not rush forward with the wild ones into the net, but return back again safe into the' pond; or if any of them should be driven forward, they are easily, by their colour, distinguished from the wild ones. Although our account more particularly relates to the bird in its wild state, it will not be improper to mention that the rearing of ducks is made an object of great importance in China. The greater part of them are hatched by artificial warmth; the eggs being laid in boxes of sand, are placed on a brick hearth, to which a proper degree of heat is given during the time required for hatching. The ducklings are fed with craw-fish and crabs, boiled and cut small, and afterwards mixed with boiled rice; and in about a fortnight they are able to shift for themselves. The Chinese then provide them with an old stepmother, who leads them where they are to find provender, being first put on board a "sampane," or boat, which is destined for their habitation, and from which the whole flock, often 300 or 400 in number, go out to feed, and return at command. This method is used nine months out of the twelve, for in the colder months it does not succeed; and is so far from a novelty that it may be seen everywhere, more especially about the time of cutting the rice, when the masters of the duck-boats row up and down the rivers, according to the opportunity of procuring food, which during that season is found in plenty, at the ebb of the tide, on the rice plantations, which are overflowed at high water. It is curious to see how the ducks obey their master; for some thousands belonging to different boats will feed at large on the same spot, and on a signal given, follow the leader to their respective boats, without a stranger being found among them. appears, usually bringing a fish in its beak. The So- FIRE-FLIES. June 29th.—The individual who has occasion to walk out a short distance beyond the boundaries of our city an hour or two after the sun has set, just when the shadows of night have spread deeply over the land, will have ample cause for surprise and admiration in the countless myriads of fire-flies that are to be seen, spangling the night with their airy lamps, and more particularly so, should the pathway lead him into the neighbourhood of some deep morass, or standing pool; then should he pause for a few moments to contemplate the brilliant magnificence of the scene, his attention will not fail to be drawn to the seemingly undetermined, and deviating course of their flight, though now and then he will have cause to observe some one or more of them, darting through the air like an eagle swooping for its prey, leaving a long The southern and western sides of the Shiant Isl-stream of splendour behind them in their trail, and ands, says a recent traveller in Scotland, exhibit little having too, in my opinion, the same object also in view, of the basaltick formation. The perfect stillness of as that of this kingly bird. These little fire-flies, inthe water afforded us a good opportunity of witness-dependently of the interest they give to a scene of the ing the mode in which the Soland goose, the albatross night, may truly be considered in the light of beneof the northern seas, drops for fish. Towering to a factors of the human race, for their natural food congreat height, the bird folds its wings, and descends, sists chiefly of gnats and moschetoes, vast numbers of VOL. III.-17 SOLAND GOOSE. |