S YC 



S YM 



limestone constituting one of the fresh- 

 water deposits of the Wealden group, and 

 occurring in layers varying from a few 

 inches to upwards of a foot in thickness, 

 the layers being separated by seams of 

 clay or of friable limestone. 



SUTURE [sutura, a seam). 1. A term 

 applied, in Botany, to the junction of the 

 valves of a simple carpel, as of the le- 

 gume. The junction corresponding to 

 the margins of the carpellary leaf, is 

 called the ventral suture ; that which 

 corresponds to the midrib of the carpel- 

 lary leaf, is the dorsal suture. 2. In 

 Malacology, the term suture is applied to 

 the line of junction in the whorls of 

 spiral shells, or to that line by which two 

 parts join or fit into each other. 3. In 

 Entomology, it is the line at which the 

 elytra meet and are sometimes confluent. 



SYCHNOCA'RPOUS (cruxvof, fre- 

 quent, Kapirdi, fruit). Polycarpous. A 

 term used in Botany to signify the dura- 

 tion of vegetable existence, and denoting 

 the power of bearing fruit many times 

 vrithout perishing. Those plants whose 

 stem endures many years, constantly 

 bearing flowers and fruits, as trees and 

 shrubs, are designated as caulocarpous ; 

 while those whose root endures many 

 years, but whose stems perish annually, 

 as herbaceous plants, are called rhizo- 

 carpous. 



SY'CONUS {cvKov, a fig). The Bota- 

 nical name of an aggregate fruit, con- 

 sisting of a fleshy rachis, having the 

 form of a flattened disk, or of a hollow 

 receptacle, with distinct flowers and dry 

 pericarps, as in the fig, the dorstenia, &c. 



SY'ENITE. A variety of granite con- 

 taining hornblende instead of mica, and 

 so called from its being brought from 

 Syene in Egypt. 



SY'LLOGISM (cri(X\o7t<7/i6y. a reckon- 

 ing all together ; reasoning). A demon- 

 strative argument, in which a conclusion 

 is deduced by comparison of its terms 

 with a middle term. It is a strictly logi- 

 cal form of argument, the conclusiveness 

 of which is manifest from the structure 

 of the expression alone, without any re- 

 gard to the meaning of the terms. 

 Thus- 

 All tyrants deserve death ; 

 Caesar was a tyrant ; 

 Therefore he deserved death. 



SY'LVANITE. Native tellurium^ 

 found in some of the Transylvanian ores. 



SY'LVIADiE {sijlvia, the warbler). 

 The Warblers ; a family of the Inses- 

 sores, or perching birds, or the Canta- 

 trices of Macgillivray, characterized by 

 their small size, none of them much ex- 

 ceeding the nightingale. Most of them 

 are migratory. See Dentirostres. 



SYMBOLS, CHEMICAL. An abbre- 

 viated mode of expressing the composi- 

 tion of bodies. The elementary sub- 

 stances, instead of being written at full 

 length, are indicated by the first letter of 

 their names, a second letter being em- 

 ployed when more than one substance 

 begins with the same letter, — thus C 

 stands for carbon, Al for aluminium, As 

 for arsenic, &c. These symbolic expres- 

 sions, or chemical forrmfi,lcB, are given in 

 the subjoined table. 



TABLE OF SYMBOLS 



