Page:The New International Encyclopædia 1st ed. v. 01.djvu/112

ACETYLENE. acetylene and other gases, such as nitrogen, carbonic acid gas, and especially marsh gas. We reproduce here the Perrodil burner, which, while adapted for use with pure acetylene, allows it to be sufficiently mixed with air before it reaches the point a, where it begins to burn.

Acetylene is one of the cheapest illuminants. It has, besides, the important advantage over other illuminants of being easily produced and requiring no special establishment for its manufacture. In the opinion of eminent experts, the danger connected with storing it even in large quantities is not great enough to justify a verdict against its introduction into common use.

We will mention a few other uses to which acetylene may be applied:

1. If calcium carbide were cheaper, acetylene might be used as an enricher; i.e., to increase the illuminating power of coal gas and of other combustible gases.

2. When acetylene is passed into an alkaline solution of iodine, the substance di-iodoform (C^Ii) is produced. This substance possesses the antiseptic properties of ordinary iodoform without having the strong and annoying odor of that substance. In the last few years di-iodoform has been manufactured on an industrial scale.

3. Under the influence of electric sparks acetylene combines directly with nitrogen to form prussic (hydrocyanic) acid. It might, therefore, be used in the cyanide industry.

4. A process has been patented in Germany for the manufacture of sugar from acetylene.

5. When heated with hydrogen, acetylene is converted into ethylene, and by the action of sulphuric acid and water the latter yields ordinary alcohol. It has been argued that if pure alcohol, manufactured by this method, could be substituted as an article of commerce for the highly toxic liquors so freely sold at the present day, a great deal would be accomplished toward diminishing the evil of alcoholism. Under the present conditions, however, the process would be too expensive.

Chemically, acetylene is an unsaturated compound, the first of an important series of hydrocarbons. It is said to be "unsaturated" because it combines with bromine and the other halogens without at the same time losing any of its own elements. It combines in a similar manner with hydrogen. By heating a mixture of acetylene and hydrogen, ethylene gas may be obtained, and this can be further transformed into ethane gas by the action of hydrogen in the presence of "platinum black" (finely divided platinum). Since from ethylene gas and ethane we can derive innumerable other compounds, it was a highly important problem to prepare acetylene itself directly from its elements. This problem solved, we could claim that we have been able to effect the complete synthesis of all those compounds; that is to say, that we can prepare them artificially without using any compound occurring ready formed in nature. The importance of the problem is due to the fact that it has been asserted that many such compounds could not he obtained artificially; that mysterious forces beyond human control could alone produce them. The French chemist Berthelot effected the interesting synthesis of acetylene by simply passing electric sparks between carbon poles placed in a vessel filled with hydrogen. Under such conditions the carbon of the poles combines directly with hydrogen to form acetylene.

In conclusion, another important property of acetylene may be mentioned. When acetylene is passed into a solution of a cuprous salt (say, cuprous chloride), containing some ammonia, a curious and characteristic compound of acetylene and copper is obtained, called copper acetylide. When a chemist is called upon to determine whether acetylene is present or absent in a given mixture, he tests it with a solution of cuprous chloride containing some ammonia; the formation of copper acetylide proves the presence of acetylene. It is currently believed that the explosive compound of copper and acetylene will form whenever acetylene comes in contact with metallic copper or its alloys. This idea has, however, been proved positively false; there is no danger whatever in storing acetylene in metallic vessels of any kind. Consult: W. E. Gibbs, Lighting by Acetylene, Generators, Burners, and Electric Furnaces (New York, 1899), and V. B. Lewes, Acetylene: a Handbook for the Student and Manufacturer (New York, 1900). A technical journal devoted to the acetylene industry (Zeitschrift für Calciumcarbid-Fabrikation und Acetylen-Beleuchtung) was established at Suhl in 1897 and has, since 1900, been published at Berlin.

ACHÆA, a-ke'a (Gk. Ἀχαΐα). (1.) The south- east part of Thessaly, the legendary home of Achilles. (2.) The northern part of Pelopon- nesus, bordering on the Corinthian Gulf. The land rising gradually from the coast to the hills of the interior was famed in ancient times for fertility in production of oil, wine, and fruits, while the wooded mountains contained much game. In the modern kingdom of Greece Achæa forms a nome, or department, in the extreme northwest of the Morea, and its chief town is Patras. Excepting the west coast, the land is fertile, and produces corn, wine, and oil.

In early times the Achæans held more or less aloof from participation in the affairs of the rest of Greece. There were twelve principal towns, the names of which, according to Herodotus, were Pellene, Ægeira, Ægæ, Bura, Helice, Ægium, Rhypes, Patræ, Pharæ, Olenus, Dyme, and Tritæa, and these formed a confederacy, with Helice at the head. After the destruction of Helice by an earthquake in 373 B.C., Ægium took its place as the chief city of the confederacy. The wars and rivalries which prevailed after the death of Alexander the Great brought about the complete dissolution of the ancient bond, but a new union was formed in 280 B.C., which gradually extended itself, and in a few years comprised the ten cities, Patræ, Dyme, Pharæ, Tritæa, Leontium, Ægeira, Pellene, Ægium, Bura, and Ceryneia. This second confederacy was known as the Achæan League. It first came into prominence as an important factor in Greek and Hellenic politics in 249 B.C., when Aratus joined thereto his native city, Sicyon. The aim of the league was from this time forth to free the Greek peninsula from Macedonian rule. In 242 B.C. the Macedonian garrison was driven from Corinth, and this city was brought into the confederacy. Before the last quarter of that century the league had