AMMONIA, OR AMMONIACAL GAS. PART XXVII. SECT. I. THIS gas was first discovered by Dr. Priestley. It is composed of hydrogen and nitrogen, rendered gaseous by the addition of caloric. PROPERTIES OF AMMONIA. Ammoniacal gas has a strong and very pungent odour. It extinguishes flame, yet it increases the magnitude of the flame of a taper before extinction, producing a pale yellow colour round its edge. Animals cannot breathe it without death ensuing. It is lighter than atmospheric air, in the proportion of three to five. It tinges yellow vegetable colours brown, and blue ones green. It is rapidly absorbed by cold water; by ardent spirit, essential oils, ether, charcoal, sponge, bits of linen cloth, and all porous bodies. gas, When a piece of ice is brought in contact with this it melts and absorbs the gas, while at the same time its temperature is diminished. It has no effect upon oxygen gas while cold; but when made to pass with it through an ignited tube, it detonates, and becomes decomposed. The same is the case with common air. It is also decomposed by phosphorus at high temperatures. It does not explode when mixed with hydrogen gas. Nitrogen gas has no effect upon it. Atmospheric air does not combine with it at common temperatures, but only mixes with and dilutes it. When made to pass through ignited charcoal, it forms with it a substance called prussic acid. If brought into contact with acid gases, both gases lose their gaseous form and become concrete. It has no sensible action on earths, or on the salino-terrene substances. It combines readily with acids, and unites to sulphur when both are in a state of vapour. It reduces oxyds of metals to their metallic state, and is decomposed by them. It is also decomposed by electrization and by oxygenized muriatic acid gas, &c. When exposed to the temperature of 46° it crystallizes, and when suddenly cooled down to-68° it assumes a gelatinous appearance, and has scarcely any odour.* METHODS OF OBTAINING AMMONIA. 1. Mix together equal quantities of muriate of ammonia and lime, separately powdered; introduce them into a gas-bottle or retort, apply the heat of a lamp, and receive the gas over mercury. RATIONALE.... Muriate of ammonia consists of muriatic acid and ammonia; on adding lime to it a decomposition takes place, the muriatic acid quits the ammonia and unites to the lime, in order to form muriate of lime, which remains in the retort, and the ammonia flies off in the state of gas. REMARK....In order to obtain the gas in a state of purity it is essentially necessary that a considerable quantity of the gas first disengaged be suffered to escape, on account of the common air contained in the distilling vessel and in the interstices of the ingredients. 2. Ammonia may likewise be obtained by heating the liquid ammonia of the shops (water of pure ammonia, Pharm. Lond.) in a retort placed in communication with the mercurial pneumatic trough. Fourcroy and Vauquelin, Ann. de Chim. XXIX. p. 289. VOL. I. RATIONALE.....The ammonia contained in this liquid combines with caloric, assumes the form of ammoniacal gas, and parts with the water to which it was united. REMARK.....The temperature of the fluid must not be carried so high as to cause the water to be converted into vapour, or, if this cannot be well avoided, a small vessel should be interposed between the retort and the receiver; which, when kept cool, may serve to condense the aqueous vapour which is formed, and cause the ammoniacal gas to pass in a very pure and dry state. Ammonia is likewise produced during the spontaneous decomposition of animal and vegetable substances; in these cases it did not pre-exist in them ready formed, but is generated by the union of the hydrogen and nitrogen contain ed in them. SECT. II. EXPERIMENTAL PROOFS OF THE PROPERTIES OF AMMONIA. EXPERIMENT I. Ammonia is absorbed by water, ardent spirit, &c. INTRODUCE into a jar filled with ammonia standing over mercury a little water, ardent spirit, or a piece of moistened sponge, paper, &c. In whichever manner the experiment is made there will be an absorption; the gas becomes absorbed, and the mercury rises in the jar so as to fill it entirely, provided the gas be sufficiently pure. If water be presented to this gas in the state of ice, it melts rapidly. REMARK..... Water which has absorbed the gas acquires its peculiar odour, and constitutes what is called liquid ammonia, or, more properly, solution of ammonia in water. From this fluid the gas may be again liberated by heat. EXPERIMENT II. Ammonia extinguishes light, but increases the magnitude of the flame before its extinction. A burning taper dipt several times successively into a bottle filled with ammonia is extinguished every time, but before its extinction the flame is enlarged by the addition of another one of a pale yellow colour, and at length this light flame will extend from the top of the vessel to the bottom. If the lighted taper be only presented to the mouth of a vessel filled with ammonia, the yellowish flame will rise considerably higher than that of the taper. EXPERIMENT III. Ammonia is lighter than atmospheric air. Let a jar filled with ammonia be placed with its mouth upwards, and left in that situation for a few minutes; it will be found to have exchanged its contents for common air, which, being heavier, descends and displaces the gas. EXPERIMENT IV. Ammonia is heavier than hydrogen gas. Put a quantity of hydrogen gas into a long tube; add to it half the quantity of ammonia, and to this a like quantity of muriatic acid gas. The two latter gases will combine and form a white cloud (muriate of ammonia) but the cloud will not rise within the space occupied by the hydrogen gas; consequently the latter had kept its place below the other without mixing with it. That the ammonia is lighter than the muriatic acid gas is shown from the formation of the white cloud on their mixture; for it begins at the bottom, and gradually reaches the top when the muriatic acid gas is last added; but when the ammonia is presented to the muriatic acid gas, the whole becomes cloudy immediately. EXPERIMENT V. Ammonia tinges yellow vegetable colours brown, and blue ones green. This may be shown by pasting a piece of paper coloured yellow with turmeric, or blue with cabbage juice, into the top of a receiver, and exposing it to the action of the gas. The first will soon become brown, and the latter green. The same effect may be produced by holding the papers over a bottle filled with water impregnated with ammonia. EXPERIMENT Vİ. Carbonic acid gas and ammonia readily unite and form carbonate of ammonia. Fill a vessel with carbonic acid gas over mercury, and add ammonia; a white vapour will instantly be formed, heat becomes evolved, the gases disappear, and carbonate of ammonia crystallizes on the inside of the vessel. EXPERIMENT VII. Ammonia becomes decomposed by oxygenized muriatic acid gas at common temperatures. Mix in a receiver over mercury two parts of oxygenized muriatic acid gas with one part, by measure, of ammonia. When these two bodies come in contact, a brisk detonation is produced, accompanied with a yellowish light; the two gases decrease in volume, and there is formed a portion of solid matter (muriate of ammonia) which adheres to the sides of the vessel. The gas which remains has no odour like ammonia, nor colour like muriatic acid gas. It is not dissolved in water, nor does it maintain combustion; it is therefore nitrogen gas. In the bottom of the vessel there is found a clear and transparent liquid, which is water, holding a certain quantity of the muriate of ammonia in solution. RATIONALE....Ammonia consists of nitrogen and hy-. drogen dissolved in caloric. Oxygenized muriatic acid gas consists of muriatic acid, oxygen, and caloric. On bringing the two gases into contact, a reciprocal decomposition takes place. The oxygen of the oxygenized muriatic acid gas combines with the hydrogen of the ammonia, and forms water; while the nitrogen, the other component part of the ammonia, becomes disengaged. The oxyge |