AMM 



AMM 



-nor does it like them corrode those ani- 

 mal bodies lo which it is applied ; its 

 smell is remarkably pungent, though not 

 unpleasant when sufficiently diluted. Its 

 use as a stimulant to prevent fainting is 

 well known. Animals cannot breathe it 

 without death. When a lighted candle is 

 let down into this gas, it goes out three 

 or four times successively ; but at each 

 time the flame is considerably enlarged 

 by the addition of another flame of a pale 

 yellow colour, and at last this flame de- 

 scends from the top of the vessel to the 

 bottom. Its specific gravity, according to 

 the experiments of Kirwan, is 0.60, that of 

 air being 1.00; while Mr. Davy, whose gas 

 was probably purer, found it 0.55. At 

 the temperature of 60, a hundred cubic 

 inches of this gas weigh, according to 

 Kirwan, 18.16 grains, according to Davy, 

 17.068. Hence it is to common air nearly 

 as 3 to 5. When exposed to a cold of 

 45 it is condensed into a l ; quid, which 

 again assumes the gaseous form when the 

 temperature is raised. When passed 

 through a red hot tube of porcelain or 

 glass, it is totally decomposed, and con- 

 verted into hydrogen and azotic gas. It 

 combines very rapidly with water. When 

 a bit of ice is brought into contact with 

 this gas, it melts, and absorbs the ammo- 

 nia, while at the same time its tempera- 

 ture is diminished. Cold water absorbs 

 this gas almost instantaneously, and at the 

 -same time heat is evolved, and the spe- 

 cific gravity of the water is diminished. 

 Water is capable of absorbing and con- 

 densing more than a third of its weight 

 of ammoniacal gas. It is in this state 

 that ammonia is usually employed by 

 chemists. The term ammonia almost 

 always means this liquid solution of am- 

 monia in water. When heated to the 

 temperature of about 130, the ammonia 

 separates under the form of gas. When 

 exposed to the temperature of 46, it 

 crystallizes ; and when suddenly cooled 

 down to 68, it assumes the appearance 

 of a thick jelly, and has scarcely any 

 smell. It follows, from the experiments 

 of Mr. Davy, that a saturated solution of 

 ammonia is composed of 



74.63 water. 

 25.37 ammonia. 



100.00 



Charcoal absorbs ammoniacal gas, but 

 does not alter its properties while cold. 

 But when the gas is made to pass through 

 red hot charcoal, part of the charcoal 



combines with it, and forms a substanee 

 known by the name of Prussic acid. Am- 

 monia is not acted on by azote ; but it 

 combines rapidly with muriatic acid ; the 

 two gases concreting into the solid salt 

 called muriate of ammonia. Ammonia 

 does not combine with the metals ; but 

 it changes some of them into oxydes, and 

 then dissolves them. Liquid ammonia is 

 capable of dissolving the oxydes of silver, 

 copper, iron, tin, nickel, zinc, bismuth, 

 and cobalt. When digested upon the 

 oxydes of mercury, lead, or manganese, 

 it is decomposed, water is formed by the 

 union of the hydrogen of the ammonia 

 with the oxygen of oxydes, and azotic 

 gas is emitted. If a considerable heat be 

 applied, nitric acid is formed at the same 

 time with water. Several other oxydes 

 are also partly deoxidized, when ammo- 

 nia is poured into their solutions in acids. 

 See ALKALI, CHEMISTUT, &c. 



AMMONIAC, in chemistry, a gum re- 

 sin brought from the East Indies. It is 

 supposed to be a species of the Ferula. 

 It is in small pieces agglutinated toge- 

 ther, and has a yellowish white colour. Its 

 smell is like that of the galbanum, but 

 more pleasant. Its taste is a nauseous 

 sweet, mixed with bitter. It does not melt. 

 Water dissolves a portion of it ; the so- 

 lution is milky, but gradually lets fall a 

 resinous portion. One-half is soluble in 

 alcohol. Its specific gravity is 1.2. Nei- 

 ther alcohol nor water, distilled off it, 

 brings over any thing. 



AMMONITRUM. See GLASS. 



AMMOPHILA, in natural history, the 

 sand-tvasp, a genus of insects of the order 

 Hymenoptera : gen. char, snout conic, in- 

 flected, concealing a bifid retractile tubu- 

 lar tongue: jawsforcipated, three-toothed 

 at the tip ; antennae filiform in each sex, 

 with about 14 articulations : eyes oval : 

 wings plain : sting pungent, concealed in 

 the abdomen. This genus is separated 

 from that of the sphex, on the authority 

 of the Rev. Mr. Kirby : in their manners 

 and economy they resemble each other; 

 and it is probable that many more of the 

 spheges might with propriety be removed 

 into this genus. There are four species : 

 A. vulgaris inhabits Europe, in sandy, 

 sunny banks, where it digs ahole with its 

 fore-feet, and buries the carcase of the 

 larva of a moth or half dead spider, in the 

 body of which it has deposited its eggs, 

 and then covers up the orifice. 



AMMUNITION, a general term for all 

 warlike provisions, but more especially 

 powder, ball,8tc. 



Ammunition, arms, utensils of war, 



