SIL 



062 



SIL 



Ph. atlas, which produces it in largest 

 quantity ; and the Ph. bombyx, which is 

 the silkworm generally known in Europe. 

 The silkworm feeds on the leaves of the 

 mulberry, and spins an oval cocoon of a 

 close tissue, very fine, usually of a yellow 

 colour, and sometimes white. A variety 

 is now preferred, which yields the latter. 

 The bombyx which produces it was ori- 

 ginally from the northern provinces of 

 China. According to Latreille, the city 

 of Turfan, in Little Bucharia, was for 

 a long time the rendezvous of the western 

 caravans, and the chief entrep6t of the 

 Chinese silks. It was the metropolis of 

 the Seres of Upper Asia, or of the Serica 

 of Ptolemy. Driven from their country 

 by the Huns, the Seres established them- 

 selves in Great Bucharia and in India. It 

 was from one of their colonies, Ser-hend 

 (Ser-indi}, that the Greek missionaries, in 

 the reign of Justinian, carried the eggs of 

 the silkworm to Constantinople. At the 

 period of the first Crusades the cultivation 

 of silk was introduced into Naples from the 

 Morea, and, several centuries afterwards, 

 under the administration of Sully parti- 

 cularly, into France, to which it is now a 

 great source of wealth. Silk was formerly 

 sold for its weight in gold. 



SILK'-THROWER, ( One who throws 



SILK/-THROWSTER. j silk. Thrown silk 

 is formed of two, three, or more singles, 

 according to the substance required, to 

 be twisted together in a contrary direc- 

 tion to that in which the singles of which 

 it is composed are twisted. The singles 

 are the reeled threads, twisted in order 

 to give strength and firmness ; and the 

 process of throwing the singles is termed 

 organzining ; and the silk so twisted is 

 called organzine. The art of throwing 

 was long kept a secret in Italy ; and be- 

 coming known in this country, the silk- 

 throwsters were reckoned a superior 

 class, and united (1562) into a fellowship. 



SILK'WORM. See SILK. 



SILL. 1. Among builders, the timber or 

 stone at the bottom of a door ; one of the 

 bottom pieces supporting quarter and 



truss partitions. 2. Among miners, a 



name in Devonshire for a variety of shell, 

 found in some mines. It is used for 

 making a peculiar sort of fire-brick. 



SIL'LON. In fortification, an elevation 

 of earth raised in the middle of a moat, 

 to defend it when it is too wide. 



SII/PHA.. A genus of coleopterous in- 

 sects belonging to the family Claricornes, 

 now divided into various subgenera, 

 known by the general name of Carrion- 

 beetles, from their habit of burying the 

 bodies of moles, mice, and other small 

 ouadrupeds. 



* SILT. Mud: the alluvial soil washed 

 down and deposited upon the bottoms and 

 udt>* of rivers by the action of the tides. 



The term is also indicative of any soft 

 " ght description of soil. 



SILU'RID.E. A family of malacoptery- 

 gious abdominal fishes, founded on the 

 genuS Siltirus, Lin. The family is dis- 

 tinguished from all others of the order 

 by the want of true scales, having merely 

 a naked skin or large osseous plates. 



SILC'BIAN. In geology, the name given 

 by Mr. Murchison to an upper subdivision 

 of the sedimentary strata found below 

 the old red sandstone, on account of the 

 strata composing this group being best 

 developed in that portion of England and 

 "\Vales formerly included in the ancient 

 British kingdom of the Silures. 



SILC'BUS. The name of a genus of 

 fishes. Order Malacopterygii abdominales : 

 family Siluridee. Name from g-tiv, to 

 move or shake, and ougot, a tail. The 

 species are numerous, and are easily re- 

 cognised by their nudity, by the mouth 

 being cleft in the extremity of the snout, 

 and by the strong spine which forms the 

 first ray of the pectoral. They are pro- 

 perly named Cat-fish. The S. glanis, Lin., 

 or Sly, is the largest fresh- water fish of 

 Europe, and the only one of the genus 

 found in it. It is found in the German 

 and Hungarian rivers, and in the lake of 

 Haarlem. The S. electricus, Lin., is an 

 inhabitant of the rivers of Africa. 



SIL'VAN. An old name for the metal 

 tellurium. 



SIL'VER, Ger. silber ; Goth, silnbr. One 

 of the precious metals, nearly white when, 

 pure ; superior to gold in lustre, but in- 

 ferior to it in malleability, though it may 

 be beaten into leaves not exceeding the 

 100,000th of an inch in thickness. It is 

 highly ductile, and surpasses gold in 

 tenacity, but in this respect is inferior to 

 iron, copper, and platinum. Its hardness 

 is between gold and copper ; it melts at 

 about 1000 F. ; has a sp. gr. of 10 47 ; and 

 is not oxidated by exposure to the atmo- 

 sphere. Europe has some silver-mines ; 

 but the metal has hitherto been found in 

 greatest abundance in South America. 

 Silver is hardened for domestic purposes, 

 and for coinage, by an alloy of copper: 

 standard silt-er consists of 11 oz. 2 dwts. of 

 silver and 18 dwts. of copper. S;SIHLLINO. 



SIL'VERIXO. 1 The art of covering the 

 surfaces of bodies with a thin film of 

 silver. The processes are nearly the 



same as gilding. 2. The silvering upon 



the back of the glass- plates of mirrors is, 

 however, an amalgam of tin. 



SII/VER-LEA.F. Silver beaten out into 

 thin leaves for silvering, exactly in the 

 same manner as gold-leaf. 



SIL'VIC ACID. That portion of resin 



which remains undissolved when turpen- 



. tine, freed from its oil, is digested in 



I cold alcohol of 0'867, has been called 



