SIL 



SIL 



dticc salivation, or an increased flow 

 of saliva. 



SICKLE. The reaping hook. See 

 Harvext. 



S r F: N I T E, SYENITE. A gray 

 granite ; Boston granite : it contains 

 hornblend in the place of mica. 



SI LEX. SILICIC ACID. Pnre 

 sand, rock crystal. This familiar body 

 is an acid, and consists of I e(iuiva- 

 lent of silicium (22-22), a body resem- 

 bling in appearance charcoal, and 3 

 cipiivalents of oxygen, 40 22. In the 

 cold it is inactive, but at a white heat 

 it forms an exceedingly active acid, 

 combining with bases, and displacing 

 most other acids, except the phos- 

 phoric and horacic. The silicates are 

 nearly all insoluble in pure water ; 

 glass and coumion earthen-ware are 

 sj)ecimcns of silicates, but they grad- 

 ually decay in the presence of acids, 

 and of carbonic acid and water. But 

 the compounds of silicic acid, with 

 two or three times its weight of car- 

 bonate of potash or soda, are soluble 

 silicates, and have been recommend- 

 ed as manures for the cerealia, which 

 always contain a large amount of si- 

 licic acid in their stems, leaves, and 

 husks. Most of the minerals and 

 rocks of the earth are silicates, this 

 acid forming from one quarter to one 

 third of its entire solid mass. 



Soluble and other silicates are 

 formed by fusing together sand and 

 the desired chemical body, usually in 

 the state of carbonate, in a black-lead 

 crucible, at a full red heat. 



The stores of potash, soda, lime, 

 and magnesia in the soil which sup- 

 [)ly plants with saline matters, are 



often in the form of silicates ; these 

 are slowly decomposed under the in- 

 fluence of the cari)onic acid of the 

 air, or from decaying vegetable mat- 

 ter, which converts tliem into soluble 

 carbonates, whereby they gain ac- 

 cess to the plant. 



SILICATES. Salts containing si- 

 licic acid ; they are usually flinty and 

 insoluble : slate, feldspar, and granite 

 are specimens. 



SILICULA. " A fruit exactly sim- 

 ilar to that called a siliqua, except 

 that it is shorter, and contains fewer 

 seeds. It is never more than four 

 times as long as broad, and usually 

 much shorter." 



SILIQUA, SILIQUE. " A one or 

 two celled, many-seeded, linear fruit, 

 dehiscent by two valves separating 

 from a septum ; the seeds are at- 

 tached to two placenta adhering to 

 the septum, and opposite to the lobes 

 of the stigma. The fruit of the mus- 

 tard is an example." 



SILIQUOSE PLANTS. Improper- 

 ly applied to leguminous plants, but 

 properly to the cruciferous family. 



SILK. On this subject much has 

 been written and said of late ; there 

 is no question that by judicious man- 

 agement a good profit can be made 

 by raising the worms. 



The silk worm is the larva or cat- 

 erpillar of the Phalana bombyx {Bom- 

 byx mori, Lin.) ; a represents the male, 

 and b the female moths ; c, the grub, 

 or chrysalis. The eggs are hatch- 

 ed in April or May, but may be kept 

 back until the end of May by placing 

 them in a cool, dry place. The eggs 

 should be hatched in parcels, and not 



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