KEYSTONE

keystone, the central voussoir of an arch (q.v.). the etruscans and the romans emphasized its importance by decorating it with figures and busts, and, in their triumphal arches, projected it forward and utilized it as an additional support to the architrave above. throughout the italian period it forms an important element in the design, and serves to connect the arch with the horizontal mouldings running above it. in gothic architecture there is no keystone, but the junction of pointed ribs at their summit is sometimes decorated with a boss to mask the intersection. key west (from the spanish _cayo hueso_, "bone reef"), a city, port of entry, and the county-seat of monroe county, florida, u.s.a., situated on a small coral island (41⁄2 m. long and about 1 m. wide) of the same name, 60 m. s. w. of cape sable, the most southerly point of the mainland. it is connected by lines of steamers with miami and port tampa, with galveston, texas, with mobile, alabama, with philadelphia and new york city, and with west indian ports, and by regular schooner lines with new york city, the bahamas, british honduras, &c. there is now an extension of the florida east coast railway from miami to key west (155 m.). pop. (1880), 9890; (1890), 18,080; (1900), 17,114, of whom 7266 were foreign-born and 5562 were negroes; (1910 census), 19,945. the island is notable for its tropical vegetation and climate. the jasmine, almond, banana, cork and coco-nut palm are among the trees. the oleander grows here to be a tree, and there is a banyan tree, said to be the only one growing out of doors in the united states. there are many species of plants in key west not found elsewhere in north america. the mean annual temperature is 76° f., and the mean of the hottest months is 82.2° f.; that of the coldest months is 69° f.; thus the mean range of temperature is only 13°. the precipitation is 35 in.; most of the rain falls in the "rainy season" from may to november, and is preserved in cisterns by the inhabitants as the only supply of drinking water. the number of cloudy days per annum averages 60. the city occupies the highest portion of the island. the harbour accommodates vessels drawing 27 ft.; vessels of 27-30 ft. draft can enter by either the "main ship" channel or the south-west channel; the south-east channel admits vessels of 25 ft. draft or less; and four other channels may be used by vessels of 15-19 ft. draft. the harbour is defended by fort taylor, built on the island of key west in 1846, and greatly improved and modernized after the spanish-american war of 1898. among the buildings are the united states custom house, the city hall, a convent, and a public library. in 1869 the insignificant population of key west was greatly increased by cubans who left their native island after an attempt at revolution; they engaged in the manufacture of tobacco, and key west cigars were soon widely known. towards the close of the 19th century this industry suffered from labour troubles, from the competition of tampa, florida, and from the commercial improvement of havana, cuba; but soon after 1900 the tobacco business of key west began to recover. immigrants from the bahama islands form another important element in the population. they are known as "conchs," and engage in sponge fishing. in 1905 the value of factory products was $4,254,024 (an increase of 37.7% over the value in 1900); the exports in 1907 were valued at $852,457; the imports were valued at $994,472, the excess over the exports being due to the fact that the food supply of the city is derived from other florida ports and from the west indies. according to tradition the native indian tribes of key west, after being almost annihilated by the caloosas, fled to cuba. there are relics of early european occupation of the island which suggest that it was once the resort of pirates. the city was settled about 1822. the seminole war and the war of the united states with mexico gave it some military importance. in 1861 confederate forces attempted to seize fort taylor, but they were successfully resisted by general william h. french. khabarovsk (known as khabarovka until 1895), a town of asiatic russia, capital of the amur region and of the maritime province. pop. (1897), 14,932. it was founded in 1858 and is situated on a high cliff on the right bank of the amur, at its confluence with the usuri, in 48° 28 n. and 135° 6 e. it is connected by rail with vladivostok (480 m.), and is an important entrepot for goods coming down the usuri and its tributary the sungacha, as well as a centre of trade, especially in sables. the town is built of wood, and has a large cathedral, a monument (1891) to count muraviev-amurskiy, a cadet corps (new building 1904), a branch of the russian geographical society, with museum, and a technical railway school.