ARCHERY 231 ARCHITECTURE ARCHERY, the art of shooting with a bow and arrow. This art, either as a means of offense in war, or as subsistence and amusement in time of peace, may- be traced in the history of almost every nation. In the Middle Ages, the bow was much more used by the burghers than by the barons. The Swiss were famous archers. In modern times, this weapon is used by the Asiatic nations, by the tribes of Africa, by the American In- dians, etc. This weapon was the leading arm of the English people for centuries. Great dependence was placed upon arch- ers in war; and frequently has the suc- cess of a battle been attributed to their means, as at Cressy, Poitiers, and Agin- eourt. Most of the English sovereigns had a bodyguard entirely consisting of archers. In the reign of Charles II. the Royal Company of Archers, as it was called, became merged in the Artillery Company of London. ARCHILL, ARGOL, ORCHILL, or ORCHAL, two species of lichen, the rocella tinctoHa and R. fusiformis, which grow in the Canary and Cape Verde Islands. They are found on rocks near the sea. They produce a fine but fugitive purple dye, and are largely employed for that purpose. Other lichens, such as the variolaria arcirm, the lecanora tartarea, etc., are sometimes used in place of the rocella. ARCHIMEDES (ar-ke-me'des), the most famous of ancient mathematicians, was a native of Syracuse. He possessed equal knowledge of the sciences of as- tronomy, geometry, hydrostatics, mechan- ics, and optics. Among his inventions were the combination of pulleys for lift- ing heavy weights, the revolving screw, and a spherical representation of the motion of the heavenly bodies. When Syracuse was taken by storm Archi- medes was killed (212 B. c). His burial place was afterward discovered by Cicero. Nine of the works of Archimedes have descended to posterity. ARCHIMEDES, PRINCIPLE OF, a well known principle in hydrostatics, the discovery of which is attributed to the celebrated philosopher whose name it bears. This important theorem may be thus defined: When a solid is immersed in a fluid, it loses a portion of its weight, and this portion is equal to the weight of the fluid which it displaces, that is, to the weight of its own bulk of the fluid. This ingenious method _ is one way of ascertaining the specific gravity of solids, but it is not the most exact. ARCHIMEDIAN SCREW, or SPI- RAL PUMP, a machine invented by Archimedes, the celebrated Syracusan philosopher, while studying in Egypt. Observing the difficulty of raising water from the Nile to places above the reach of the flood tides, he is said to have de- signed this screw as a means of over- coming the obstacle. It consists of a pipe twisted in a spiral form around a cylinder, which, when at work, is sup- ported in an inclined position. The lower end of the pipe is immersed in water, and when the cylinder is made to revolve on its own axis, the water is raised from bend to bend in the spiral pipe until it flows out at the top. The Archimedian screw is still used in Hol- land for raising water, and draining low grounds; there it is mostly of large size and moved by the wind. ARCHIPELAGO, a term applied to such tracts of sea as are interspersed with many islands. It is more especially applied to the numerous islands of the JEgean Sea, or that part of the Mediter- ranean lying between Asia Minor and Greece. These islands are principally divided into two groups called the Cy- clades and Sporades. The former con- tains the islands of Kythnos, Lyra, Se- riphos, Keos, Anoros, Tenos, Naxos, Thera, los, Melos, Kimolos, etc., all be- longing to Greece, and forming the prov- ince of the Cyclades. The Sporades group consists of Scio, Cos, Rhodes, Sa- mos, Mitylene, Lemnos, etc. ARCHITECTURE, the art of building or constructing. However elaborate and diversified the edifices of different times and countries may be, all their styles may be traced back to the two chief building materials? wood and stone. Wooden construction manifests itself in upright pillars with beams laid across them, hence called the trabeate system; genuine stone building is distinguished by the employment of the arch with its abutments. Most of the nations of an- tiquity, notably Egypt and Greece, al- though acquainted with the arch, ad- hered to the earlier and simpler trabeate type of the pillar and beam; and the details of their architecture, although executed in stone, show evidences of their wooden origin in the traditional wooden features of triglyphs, metopes, etc., with moi-tar or cement. After they had learned to build houses, they erected temples for their gods on a larger and more splendid scale than their own dwell- ings. The Egyptians are the most an- cient nation known to us among whom architecture attain*^d the character of a fine art.
