Page:Collier's New Encyclopedia v. 01.djvu/45

ACETIC ETHERS soluble. Aluminum acetate is used in dyeing. Lead acetate is called sugar of lead, from its sweet taste. It dissolves in 1% parts of cold water; it also dissolves oxide of lead, forming a basic acetate of lead. Basic cupric acetate is called verdigris. Acetic acid below 15.5° forms colorless transparent crystals (glacial acetic acid), which melt into a thin, colorless, pungent, strongly acid liquid, soluble in alcohol, ether, and water. It boils at 118°. Its vapor is inflammable.

Pyroligneous acid is impure acetic acid, formed by the destructive distillation, at red heat, of dry hard wood, as oak and beech.

ACETIC ETHERS [example, ethyl acetate,

C2H3O I f\-t CM. S "J

are formed by replacing the typical H in acetic acid by a radical of an alcohol, as ethyl, etc. Ethyl acetate is a fragrant liquid, sp. gr. 0.890, boils at 74°; methyl acetate boils at 56°.

ACETONES, or KETONES, are the aldehydes of secondary alcohols (see ALCOHOL). Thus secondary propyl alcohol, when oxidized, loses two atoms of hydrogen, and gives dimethyl ketone, ordinarily known as acetone.

Secondary Propyl Alcohol. Acetone CH.— CHOH— CH3— H,=CH.-CO— CH,.

A series of such acetones is known, of which acetone is typical. It may be prepared by distilling acetate of calcium. It is a limpid liquid, having a taste like that of peppermint, and is readily soluble in alcohol, ether, and water. Its sp. gr. is about .79, its boiling point being 130° F. (56° C). It has recently been used in America for the manufacture of chloroform, which is obtained from it by distillation with bleaching-powder. It is a solvent for gums and resins, as well as for gun-cotton.

ACETYLENE, a hydrocarbon having the formula C2H2, also called ethine. The carbon atoms are united to each other by three bonds. It is produced by passing an electric current between carbon poles in an atmosphere of hydrogen, and also by the incomplete combustion of hydrocarbons. It is a colorless gas, specific gravity, 0.92, has a peculiar odor, and burns with a bright flame; it forms a red precipitate with ammoniacal cuprous chloride, which, by the action of nascent hydrogen, is converted into ethylene, C2H4.

ACETYLENE GAS, an illuminating gas formed by the action of water on CALCIUM CARBIDE (q. v.). This gas has come into general favor with cyclists for its brilliancy, safety, and the persistence of its flame in all circumstances. Recent experiments made to produce cheaper calcium carbide, by a new process, resulted in demonstrating that it can be produced at a cost of from half a cent to three cents a pound, or one-fifth its original cost. This will bring acetylene gas within the reach of every one, and it will probably eventually supersede many other forms of lighting. One kilogram of calcium carbide produces about 300 litres of acetylene gas. Acetylene takes fire at 480° Cent.; at 700° it decomposes into carbonic acid and hydrogen.

ACETYLENE LAMP, a lamp designed for utilizing acetylene as an illuminant. Acetylene lamps have come into general use among cyclists. In some of the lamps, cartridges filled with calcium carbide are used, and the dropping of the water into the cartridge is regulated by an adjustable valve. The acetylene flame is very brilliant.

ACHÆA, a Greek province. See ACHAIA.

ACHÆANS, a generic term employed by Homer to designate the whole Hellenic host before Troy, from their mythological ancestor, Achæus, grandson of Helen.

ACHÆI (ak-ā-ē, or ak-ī´ē), the descendants of Achæus, the son of Zuthus, and grandson of Helen. Achæus, having committed manslaughter, was compelled to take refuge in Laconia, where he died, and where his posterity remained under the name of Achæi, until they were expelled by the Heraclidæ. Upon this, they passed into the northern parts of Peloponnesus, and, under the command of Tisamenus, the son of Orestes, took possession of the country of the lonians, and called it Achaia. The successors of Tisamenus ruled until the time of Gyges' tyranny, when Achaia was parceled into 12 small republics. Three of these—Patræ, Dymæ, and Pharæ—became famous as a confederacy, 284 B. C, under the name of the Achæan League. At last, however, they were attacked by the Romans, and, after one year's hostilities, the Achæan League was totally destroyed, B. C. 147.

ACHAIA, a small Greek district lying along the N. coast of the Peloponnesus. Achaia forms, along with Elis, a department in the modern kingdom, and its chief town is Patras. As the Achaians (Achæans) were the ruling people of the Peloponnesus in heroic times. Homer speaks of the Greeks generally as Ach-