Arcature, in architecture, a small arcade built into a wall or applied against it, decorative rather than structural. Arcatures occur in Anglo-Norman churches of the twelfth and thirteenth centuries.
Arcesilaus (a˙r-ses-i-lā´us), a Greek philosopher, the founder of the second or middle academy, was born about 315 B.C., died 239 B.C. He left no writings, and of his opinions so little is known that it has been doubted whether he was a strict Platonist or a sceptic.
a. Abutments. i. Impost. p. Piers. v. Voussoirs or arch-stones. k. Keystone. s. Springers. In. Intrados. Ex. Extrados.
Archæan (är-kē´an) Rocks (Gr. archaios, ancient), the oldest rocks of the earth's crust,
mostly crystalline in character, and embracing granites, gneisses, mica-schists, &c., all devoid of fossil remains. These rocks underlie a group of stratified and igneous masses that are usually distinguished from them as Huronian; the first beds with a well-marked fauna (lowest Cambrian) lie above the Huronian, and the Huronian and the Archæan groups are often conveniently classed together as pre-Cambrian, and are separated from the stratified and fossiliferous formations, which indeed have chiefly taken origin from them. The core of the Malvern range, and the rocks of N.W. Sutherland, are examples of Archæan masses in Great Britain.
Archæol´ogy (Gr. archaios, ancient, and logos, a discourse), the study of antiquity, or the science which takes cognizance of the history of nations and peoples as evinced by the remains, architectural, implemental, or otherwise, which belong to the earlier epoch of their existence. In a more extended sense the term embraces every branch of knowledge which bears on the origin, religion, laws, languages, science, arts, and literature of ancient peoples. It is to a great extent synonymous with prehistoric annals, as a large if not the principal part of its field of study extends over those periods in the history of the human race in regard to which we possess almost no information derivable from written records. Archæology divides the primeval period of the human race, more especially as exhibited by remains found in Europe, into the stone, the bronze, and the iron ages, these names being given in accordance with the materials employed for weapons, implements, &c., during the particular period. The stone age has been subdivided into the palæolithic and neolithic, the former being that older period, in which the stone implements were not polished as they are in the latter and more recent period. The bronze age, which admits of a similar subdivision, is that in which implements were of copper or bronze. In this age the dead were burned and their ashes deposited in urns or stone chests, covered with conical mounds of earth or cairns of stones. Gold and amber ornaments appear in this age. The iron age is that in which implements, &c., of iron begin to appear, although stone and bronze implements are found along with them. The word age in this sense (as explained under Age) simply denotes the stage at which a people has arrived. The phrase stone age, therefore, merely marks the period before the use of bronze, the bronze age that before the employment of iron, among any specific people. See Excavations; Crete; Egypt; &c—Bibliography: Sir J. Evans, Stone Implements of Great Britain; Boyd-Dawkins, Early Man in Britain; J. Geikie, Prehistoric Europe; R. Munro, Lake Dwellings of Europe; Sir W. Ridgeway, Early Age of Greece; H. R. Hall, Ægean Archæology; W. M. Flinders Petrie, Methods and Aims in Archæology; A. P. F. Michaelis, A Century of Archæological Discoveries.