A M M A M M 741 not being older than the Persian rulers of Egypt, while the worship of the god at Thebes dates from a much older epoch. The later chapters of the Ritual, added at the time of the twentieth dynasty, which contain the mystic names and appellatives of the god in the language of the negroes of Punt, are also of too late a date to throw any light on the origin of Amen, which appears prior to the Hykshos, when the Egyptian princes were driven to the south. The sheep was sacred to the god, and the inhabitants of Thebes in consequence abstained from it; but it is said they annually sacrificed a ram to Amen, and dressed the figure of the god in the hide of the animal. The reasons assigned by classical authorities for this action, as well as for the astronomical meaning of his horns, are not confirmed by monumental evidence. On the conquest of Egypt Alex ander the Great called himself the son of Ammon, and his portraits wear the ram s horn. In this he had only imitated the Pharaohs of the nineteenth dynasty. Amen is only mentioned by the Hebrew prophets in speaking of Diospolis as the city of No or No Amon. Jablonski, Panth. jEyypt., i. 160-184; Birch, Gallery of Antiq., pt. i. 1; Wilkinson, Manners and Customs, iii 313, iv. 246, /.; Goodwin, Trans. Soc. Bibl. Arch., ii. pp. 353-9; Herodotus, ii. 42, 54; Diodorus, iii. 72; Jer. xlvi. 25; Nah. iii. 8. (s. B.) AMMON, CHRISTOPH FEIEDRICH VON, a distinguished theological writer and preacher, was born at Baireuth in January 1766, studied at Erlangen, held various professor ships in the philosophical and theological faculties of Erlangen and Go ttingen, succeeded Reinhard in 1813 as court preacher and counsellor at Dresden, retired from these offices in 1849, and died May 21, 1850. He sought to establish for himself a middle position between rational ism and supernaturalism, inclining, however, decidedly to the former. He declared for a " rational supernaturalism," and contended that there must be a gradual development of Christian doctrine corresponding to the advance of know ledge and science. He was a man of great versatility and extensive learning, and a very voluminous author, his principal work being the FortbUdung des Christenthums zur Weltreliyion, in 4 vols. (Leipsic, 1833-40). Entwurf einer rein liblischen TJieologie appeared in 1792 (second edition, 1801), and Summa Theological 1803 (other editions, 1808, 1816, 1830). Von Ammon s style in preaching was terse and lively, and some of his discourses are regarded as models of pulpit treatment of political questions. AMMONIA (NH 3 ), sometimes called the Volatile alkali, or Alkaline air, was known to the alchemists in aqueous solution. Priestley first separated it in the gase ous state in 1774. Scheele in 1777 discovered that it contained nitrogen, and its true composition was ascer tained by Berthollet about 1785. Ammonia occurs in the atmosphere as carbonate and nitrate, in sea-water, and in many mineral springs. Iron ores and many clayey soils contain it in small quantity, and sal-ammoniac and ammonia alum are found as minerals in volcanic districts. Carbonate of ammonia is obtained in large quantity by the putrefaction of the urine of animals, or the dry distilla tion of animal matter. Ammonia is obtained from its salts by the acting of slaked lime or solutions of potash or soda, and is freed from water by passing over quick lime or solid potash, and finally collected over mercury. It is a colourless gas, of a pungent smell, and alkaline taste and reaction. It does not support combustion or respiration, and is feebly combustible. It is remark ably soluble in water, 1 volume dissolving nearly 700 of the gas. It may by the action of a low temperature and great pressure be changed into the liquid or solid state. The gas is easily decomposed into its elements by a succession of electric sparks, or by passing it over red- hot iron or platinum wire. The aqueous solution in pre sence of finely divided platinum and atmospheric air is converted into nitrite of ammonia; and conversely, the oxides of nitrogen, mixed with excess of hydrogen and passed over platinised asbestos, are changed into ammonia. Nitrogen and hydrogen have not by any process been in duced to combine so as to yield this compound directly, unless in very small quantity. For theoretical relations of ammonia, salts, &c., see CHEMISTRY. AMMONIAC, SAL (NH 4 C1), the earliest known salt of ammonia, now named chloride of ammonium, formerly much used in dyeing and metallurgic operations. The name Hammoniacus sal occurs in Pliny (Nat. Hist. xxxi. 39), who relates that it was applied to a kind of fossil salt found below the sand, in a district of Cyre- naica. It was similar in appearance to the alumen scissile, and had a disagreeable taste, but was useful in medicine. The general opinion is, that the sal-ammoniac of the ancients was the same as that of the moderns ; but the imperfect description of Pliny is far from being sufficient to decide the point. The native sal-ammoniac of Bucharia, described by Model and Karsten, and analysed by Klaproth, has no resemblance to the salt described by Pliny. The same remark applies to the sal-ammoniac of volcanoes. Dioscorides (v. 126), in mentioning sal-ammoniac, makes use of a phrase quite irreconcilable with the description of Pliny, and rather applicable to rock-salt than to our sal- ammoniac. Sal-ammoniac, he says, is peculiarly prized if it can be easily split into rectangular fragments. Finally, we have no proof whatever that sal-ammoniac occurs at present, either near the temple of Jupiter Ammon, or in any part of Cyrenaica. These circumstances induce us to conclude that the term sal-ammoniac was applied as inde finitely by the ancients as most of their other chemical terms. It may have been given to the same salt which is known to the moderns by that appellation, but was not confined to it. Some derive thename sal-ammoniacivom Jupiter Ammon, near whose temple it is alleged to have been found; others, from a district of Cyrenaica called Ammonia. Pliny s derivation is from the sand (a/x/xos) in which it occurred. Whether our sal-ammoniac was known to the ancients or not, there can be no doubt that it was well known to the alchemists as early as the 13th century. Albertus Magnus, in his treatise De Alchymia, informs us that there were two kinds of sal-ammoniac, a natural and an artificial. The natural was sometimes white, and some times red ; the artificial was more useful to the chemist. He does not tell us how it was prepared, but he describes the method of subliming it, which can leave no doubt that it was real sal-ammoniac. In the Opera Mineralia of Isaac Hollandus the elder, there is likewise a description of the mode of subliming sal-ammoniac. Basil Valentine, in his Currus Triumphalis Antimonii, describes some of the peculiar properties of sal-ammoniac in, if possible, a still less equivocal manner. Egypt is the country where sal-ammoniac was first manufactured, and from which Europe for many years was supplied with it. This commerce was first carried on by the Venetians, and afterwards by the Dutch. Nothing was known about the method employed by the Egyptians till the year 1719. In 1716 the younger Geoffrey read a paper to the French Academy, showing that sal-ammoniac must be formed by sublimation ; but his opinion was opposed so violently by Homberg and Lemeiy, that the paper was not printed. In 1719 M. Lemaire, the French consul at Cairo, sent the Academy an account of the mode of manufacturing sal-ammoniac in Egypt. The salt, it appeared, was obtained by simple sublimation from soot.
In the year 1760 Linnaeus communicated to the Royal
