Page:The New International Encyclopædia 1st ed. v. 01.djvu/555

AMMIANUS MARCELLINUS. in Rome to a quiet and studious life. His book is of great importance as the conscientious work of an experienced man; but the Latin is rude and the style is heavy and dull. The account of the events of Julian's reign is especially valuable. Best edition by Gardthausen (Leipzig, 1875); English translation by C. D. Yonge, in Bohn's Classical Library (London, 1862).

AMMIRATO, iim'me-rii'to. Scipione (1531- 1601). An Italian historian of some merit. He was born in Lecce, in the kingdom of Naples, and after living in Venice, Rome, and Naples, settled at Florence. In Venice he aided in editing an edition of Ariosto. His reputation, however, rests mainly upon his Istoric florciitiiic, which in 1570 he was commissioned to write by the Grand Duke Cosimo I., and which covers the history of Tuscany from the earliest times down to 1574. It shows distinct ability and historical acumen, and is based upon original documents and other authentic sources. First complete edition. Florence, 1641-47; best modern reprint, Turin, 1850.

AM'MON. An Egyptian deity. His name (Egyptian Amon, later Amún) was explained by the priests as meaning "the hidden," or "mysterious;" but this etymology is not reliable. Originally Ammon was merely the local god of Thebes; but after the Theban dynasties became rulers of all Egypt (beginning with the Eighteenth Dynasty, about 1600 B.C.), he became the official head of the pantheon and national deity of Egypt. His worship spread throughout Ethiopia and Libya, and he had a famous oracle in the Libyan Desert. The Greeks identified him with their supreme god Zeus, and named Thebes, his original seat of worship, Diospolis. In the Old Testament the city is called No-Ammon. "The City of Ammon."

Although not originally a solar divinity, later theological schools ascribed a solar character to this god, and he was called Ammon-Re, i.e., "Ammion the Sun." In his statues, Ammon is generally represented in human form, with skin of a bluish tint, and wearing a peculiar head-dress, from which rise two immense feathers, while a long and narrow band hangs down behind. He often appears in the form of his sacred animal, the ram, or as a ram with a man's head. Among the Greeks and Romans, the Libyan type, with a human head bearing a ram's horns, became popular. For illustration, see.

AMMON, (1842 — ). A German anthropologist and editor. He was born at Karlsruhe, and was educated as a civil engineer, which profession he followed from 1863 to 1868. He then became a publisher and editor, but in 1883 began to devote himself to literary work, and afterward made several important contributions to sociological and anthropological literature. He was the discoverer of the so-called "Ammon's law," that the Teutonic race betrays almost everywhere a marked tendency toward city life, which he has demonstrated in a series of interesting measurements of the physical characteristics, especially of the head, of thousands of conscripts in the Baden army, showing radical differences between the form of the head in city and country, and between the upper and lower classes in the larger towns. His chief works are: Die natürliche Auslese beim Menschen (Jena, 1893), Die Gesellschaftsordnung und ihre natürlichen Grundlagen (second edition, Jena, 1896), and important articles as follows: "Die Geschichte einer Idee," Rundschau (Berlin, 1896), on the physical types of city populations; "Der Abänderungsspielraum," Naturwissenschaftliche Wochenschrift (Berlin, 1896); "Die Menschenrassen in Europa," Rundschau (Berlin, 1896); "Die Körpergrösse der Wehrpflichtigen in Baden, 1840-64" (Karlsruhe, 1849); "Anthropologische Untersuchungen der Wehrpflichtigen in Baden" (1890).

AMMONIA. See.

AMMO'NIA (Gk. a/i/iavtnK6v, ammoniakon, rock-salt), NHj. A colorless, pungent, gaseous compound of nitrogen and hydrogen. It was known to the ancients as volatile alkali, and is said to have been called vehement odor by Pliny. Its name is believed to be derived from Zeus Ammon, near whose temple in Libya, Upper Africa, it was first produced by burning camels' dung. Others derive it from Ammonia, a Cyre- naic territory. In 1774 Priestley obtained it by boiling its aqueous solution and collecting the gas, which he termed alkaline air, over the mer- curial pneumatic trough. Scheele showed that it contained nitrogen, and Berthollet, in 1785, demonstrated its composition. Free ammonia does not occur in nature, but its salts are found in the atmosphere and in rain-water, in mineral and sea waters, in most plants, and as a product of the decay of nitrogenous organic bodies.

It may be made by heating ammonium chloride with lime. The principal commercial source of ammonia is from the destructive distillation of coal in gas making. In the distillation of coal in a retort, there is obtained, first, illuminating gas, and, secondly, a liquor which contains ammonia. Allowing this liquid to settle, the aqueous portion separates, from which free ammonia is first expelled by means of steam, after which the liquor is treated with lime and further steam to expel the fixed ammonia. The steam, ammonia, and other gases are passed through strong sulphuric acid in lead tanks, and the crystals of ammonium sulphate which then form are removed from time to time by means of ladles, while the free ammonia is collected in water yielding aqueous ammonia or hartshorn, a transparent, colorless, and strongly alkaline liquid with an acrid, caustic taste and pungent odor. When exposed to the air, it loses ammonia, and when reduced to minus 40° C. it freezes.

Liquid ammonia has been used for motive power, and its evaporation is the basis for the Carré and Linde processes for the production of artificial cold. It is also used in pharmacy, dyeing, calico printing, and in the preparation of coloring matters, and many chemicals.

Ammonium sulphate, which is a white crystalline compound, is largely used both alone and in mixtures as an artificial fertilizer; it is also used in the manufacture of alum, and in the preparation of other ammonium salts. Ammonium chloride, called also sal ammoniac, is used in pharmacy, in dyeing, and as a convenient source of ammonia. Ammonium carbonate, called also sal volatile, is used for scouring wool, for dyeing, and as a baking powder. Consult: Arnold, Ammonia and Ammonia Compounds (London, 1889); and Lunge, Coal Tar (London, 1882).

AMMO'NIAC (Lat. ammoniacum, Gk. a/jftu-vianoi; ammoniakon, gum-ammoniac), or Gum