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.
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Archimedes (Most famous of ancient)
most famous of ancient mathematicians, was a native of Syracuse. He possessed equal knowledge of the sciences of astronomy, geometry, hydrostatics, mechanics, and optics. cics. Among his inventions were the combination of pulleys for lifting heavy weights, the revolving screw, and a spherical representation of the motion of the heavenly bodies. When Syracuse was taken by storm Archimedes was killed (212 b. c.). His burial place was afterward discovered by Cicero. Nine of the works of Archimedes have descended to posterity.
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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 designed this screw as a means of overcoming the obstacle. It consists of a pipe twisted in a spiral form around a cylinder, which, when at work, is supported 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 Holland for raising water, and draining low grounds; there it is mostly of large size and moved by the wind.
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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 Ægean Sea, or that part of the Mediterranean lying between Asia Minor and Greece. These islands are principally divided into two groups called the Cyclades and Sporades. The former contains the islands of Kythnos, Lyra, Seriphos, Keos, Anoros, Tenos, Naxos, Thera, Ios, Melos, Kimolos, etc., all belonging to Greece, and forming the province of the Cyclades. The Sporades group consists of Scio, Cos, Rhodes, Samos, Mitylene, Lemnos, etc.
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Architrave
in architecture, the part of the entablature which rests immediately on the heads of the columns, being the lowest of its three principal divisions, the others being the frieze and the cornice.
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Archives
the place in which records are kept; also the records and papers which are preserved, as evidence of facts.
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Archivolt
in architecture, the ornamental band of moldings on the face of an arch and following its contour.
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Archons
the chief magistrates of ancient A Athens, chosen to superintend civil and religious concerns. They were nine in number; the first was properly the archon, or archon eponymos, by whose name the year was distinguished in the public records; the second was called archon basileus, or king archon, who exercised the functions of highpriest; the third, polemarchos, or general of the forces. The other six were called thesmothetai, or legislators.
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Arcograph
An instrument sometimes used by watchmakers for drawing a circular arc without the use of a central point. ARNOLD, JOHN. Born in Cornwall, England, in 1744, and died at Eltham, England, in 1799. He was the inventor of the helical form of balance spring and a chronometer escapement. The English Government awarded him pound1,320 for the superiority of his chronometers in 1799, and his son, who followed up the successes of his father, was awarded pound1,680 in 1805.
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Arcot
a city of British India, in the presidency of Madras, the capital of the district of North Arcot. It is situated on the right bank of the Palar, 65 miles W. S. W. of Madras. Arcot contains some mosques in a tolerable state of repair, and the ruins of the Nawab's palace. In 1751 Clive, with 300 Sepoys and 200 Europeans, marched against Arcot, and after having taken it, had in his turn to withstand a siege of 50 days. Arcot was afterward captured by the French, but retaken by Colonel Coote in 1760. It was taken and held for a time by Hyder Ali, but passed into the hands of the British tricts of North and South Arcot form a portion of the presidency of Madras. ARCTIC. (1) An adjective bright, and (2) a substantive a bear, so called either from his bright eyes or from his brilliant tawny fur. Before the Aryans had finally separated, riksha bright, applied to the plow-like constellation, had become obsolete, and the substantive bear remained, whence the constellation came to be called arktos among the Greeks, Ursa among the Latins, ns, and Bear among ourselves. 1. Properlv, pertaining to the constellation called by the Greeks arktos-bear, by the Romans, Ursa, and by ourselves Ursa Major, the Great Bear, the Plow, Charles' Wain, etc. 2. Pertaining to the North generally, or more especially to the region within the Arctic Circle.
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Arcturus
ark-tu'rus, as supposed by many astronomers, the nearest of the stars. It is situated in the constellation Bootes in the northern heavens. It shines with a red light. It is supposed to be a body like our own sun. It is evidently moving southward slowly through the heavens. It has moved a degree since the days of Ptolemy. It is thought by Professor C. A. Young that "Arcturus gives the earth as much heat as would be received from a standard candle 5.8 miles away." One writer hazards the statement that Arcturus is 1,500,000 times as far away as the sun, that it has a diameter of 71,000,000 miles, and that its bulk is 551,000 times that of the sun. See Star Canst thou guide Arcturus with his sons?--Job xxxviii:32. 2026 Editor's Note: Arcturus had a starring role at the 1933 Chicago World's Fair : its light — captured by telescopes — was used to switch on the fair's lamps, chosen because astronomers then thought it lay about 40 light-years off, so its rays had set out during the previous Chicago fair of 1893. It is the fourth-brightest star in the night sky. (Ed: BR 2026-07-08)
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