POWER. 333 POWERS. more parallel endless ropes are used, embracing groove-faced pulleys. Rope transmission, like belt transmission and transmission by gearing, involves the use of shafting as a part of the trans- mission system. See Shafting. The dynamic or wire rope transmission is a special development of rope transmission, whose most familiar example is perhaps the cable rail- way. The dynamic transmission is especially suited to distances up to about one mile. Water under high pressure ( 700 to 2000 pounds per square inch and upward) affords a very satisfac- tory method of transmitting power to a distance, especially for the movement of heavj- loads at small velocities, as by cranes and elevators. The system usually consists of one or more pumps ca- pable of developing the required pressure (see Plmp.s axd Pumpixg ^Machinery) ; one or more accumulators by which a quantity of water may be accumulated at the required pressure (see Accumulators) ; the distributing pipes, and the presses, cranes, or other machinery operated. ( See Hyi)r.ulic Press ; Hydraulic Pressure Engine.) Systems of hydraulic transmission for general industrial purposes exist in London, Liv- erpool. Hull, Birmingham, and JLmchester, Eng- land; in Antwerp, in Holland; in Zurich, and in Geneva, Switzerland ; and in many other places. Air under pressure is one of the most ^ten- sively employed means of power transmission at present practiced. Some of the great variety of uses to which compressed air is put at present are listed in the article on AiB Compressors. The system for compressed air transmission usually consists of an air compressor plant, including re- ceivers, for compressing air and storing it under compression (see Air Compressors), the pipes for conveying and distributing the compressed air, and the drills, hoists, and other motors oper- ated. (See Drills; Pneumatic Tools; Ham- mers; Air Brake; Compresseu-Air Locomo- tive; I'neumatic Dispatch.) The longest dis- tance to which air has ever been transmitted in America is three miles, at the Chapin mine, Iron Mountain, ^Michigan. The most modern and in some respects the most important means of power transmission is electricity, which is now used for lighting, street raihvav', and general purposes, in constantly in- creasing amounts. The system for electric power transmission consists of the generating plant of engines and dynamos (see Dynamo-Electric Machinery), the transmission line wires, cables or bars, and the motors operated. (See Electric Railways ; Electric Lighting ; Storage Bat- teries; Transformers.) One of the earliest at- tempts at long distance electric transmission was made between Mimich and Jleisbach, Germanv, in 18S2. The distance was .32 miles. In 1886 power was transmitted between Creil and Paris. France, 3fi miles, and in 1891. on the occasion of the elec- tric exhibition at Frankfort, Germany, power was transmitted from Tauffen to Frankfort. 100 miles. The longest transmission line in America is from Eedlands to Los Angeles, Cal., 80 miles. There is also a 24-inile line from Folsoni to Sacramento, Cal., and a 3.5-mile line at Provo, L'tah. Bibliography. For the best available litera- ture on power transmission, see Kent, Mechanical Enf/ineers' Pocket Booh (New York. 1900); Flather. Rope Drirhuj (N'ew York, 1895) ; Mark, Hydraulic Power Engineering (New York, 1900) ; Richards, Compressed Air (New York, 1895) ; Unwin. Development and Transmission of Power (London, 1894). POW'ER„ IVAbcy (1855—). An English surgeon, born in London. He was educated at New and Exeter colleges, Oxford; in 1878-79 was demonstrator of comparative anatomy at Univer- sity College, London, and in 1878 was appointed a demonstrator of phj'siology at Saint Bartholo- mew's Hospital, where he subsequently Ijecame assistant surgeon, teacher of surgery, and sur- geon in charge of the throat department. In 1883 he was admitted a fellow of the Royal College of Surgeons of England, in which he held the posts of examiner and Hunterian professor of surgery and pathology. He was also appointed assistant professor in the Ro.yal Veterinary Col- lege. His published writings include studies of cancer, intestinal obstruction, and other medical subjects. Memorials of the Craft of Surgery (1886), a Life of William Harvey (1897), and biographies of eminent surgeons contributed to the Dictionary of National Biography. POWER, Henry (1829—). An English oph- thalmologist, born in Nantes, France. He was educated at Cheltenham College and Saint Bar- tholomew's Hospital, in 1854 became fellow of the Royal College of Surgeons, and afterwards W'as its vice-president. He served as consulting ophthalmic surgeon to various London charities, and was appointed lecturer on physiology at Westminster Hospital and professor of physi- ology at the Royal Veterinary College. He wrote Illustrations of the Principal Diseases of the Et/e (1869), and Elements of Human Physiology (1884). POWER, ^Iarguerite. The maiden name of the English society leader Countess Blessington (q.v.). POWER, (William Grattan) Tyrone (1797- 18411. An Irish comedian, boi'n near Kilmac- thomas. County Watcrford. He was taken to Wales while a child, and there about 1813 made his first appearance on the stage. He met with little success, however, and for some time filled only minor roles. In London he made his first success in the part of Larry Hoolagan O'Halloran in 1824, and from that time confined him.self almost exclusively to the portrayal of Irish characters. His acting was distinguished by keen wit combined with tender pathos. He made four successful tours in the United States, and was lost at sea on the return voyage of the last trip. In addition to dramatizing several works, he wrote two novels and Impressions of America (2 vols., 1835). POWER OF APPOINTMENT. An author- ity or power vested in a person to create a new interest or estate in property in favor of some one whom he may select. For example, A may convey land to B for life, with piower to appoint some person to w'hom the property shall go on B's death. A power of appointment is to be distinguished from a power of revocation, which authorizes the donee of the power to divest or destroy an existing estate. Consult Sugden on Poivers; see also Power. POWERS, Hir.m (180.5-73). An American sculptor. He was bom July 29, 1805, on a small farm in Woodstock, Vt. As the farm proved insufficient for its support, his family
