AMM 



AMM 



docs it like them corrode those animal 

 bodies to which it is applied ; its smell is 

 remarkably pungent, though not unplea- 

 sant when sufficiently diluted. Its use as 

 :i stimulant to prevent fain ing- is well 

 known. Animals cannot breathe it with- 

 out death. When a lighted candle is let 

 down into this gus, 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 yel- 

 low colour, and at last this flame descends 

 from the top of the vessel to the bottom. 

 Its specific gravity, according to the ex- 

 periments 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 

 4 5 it is condensed into a liquid, 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 

 specific gravity of the water is diminish- 

 ed. Water is capable of absorbing and 

 condensing more than athird 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 ammo- 

 nia separates under the form of gas. 

 When exposed to the temperature of 

 46, it crystallizes; and when sud- 

 denly 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 satura- 

 sed solution of ammonia is composed of 



74.6.3 water. 

 25.37 ammonia. 



100.00 



Charcoal absorbs ammoniacal gas, but 

 does not alter its properties wliilc cold. 

 But when the gas is made to pass through 

 red hot charcoal, part of the charcoal 



combines with it, and forms a substance 

 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 sil- 

 ver, copper, iron, tin, nickel, zinc, bis- 

 muth, and cobalt. When digested upon 

 the oxydes of mercury, lead, or mangan- 

 ese, it is decomposed, water is formed by 

 the union of the hydrogen of the ammo- 

 nia with the oxygen of the 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 

 ammonia is poured into their solutions in 

 acids. See ALKALI, CHKMISTKY, &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 together, 

 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 

 .'and--a-f:sp,SL genus of insects of the order 

 Hymenoptera : gen. char, snout conic, in- 

 flected, concealing a bifid retractile tubu- 

 lar tongue : jaws forcipated, three-tooth- 

 ed 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 a hole 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, anil then covers up the orifice. 



AMMUNITION, a general term for all 

 warlike provisions, but more especially 

 powder, ball, Sec. 



Ammunition, arms, utensils of war, 



