SOD 



[ 239 ] 



SPA 



certain hypersthene rocks, in some eurites, 

 in trachytes, pitchstones, basalts, and 

 some diallage rocks. There can be little 

 doubt that a large amount of soda is 

 thus locked up in rocks, particularly if 

 we include the masses of rock-salt disco- 

 vered in different parts of the world. It 

 is, however, found in greatest abundance 

 diffused through the waters of the ocean. 



SO'DA FE'LSPAR. Another name for albite, 

 or tetarto-prismatic felspar. See Albite. 



SO'DALITE. (from soda, and Xi'0oe, Gr. a 

 stone.) A sub-species of lapis lazuli. 

 The name sodalite has been given to this 

 mineral from the large proportion of soda 

 which it contains, being 25 per cent. Its 

 constituents are silex 36''0, alumine 32'0, 

 soda 25-0, muriatic acid 6'7, oxide of 

 iron 0-2. It is found in Greenland and 

 Vesuvius. It occurs massive, and in do- 

 decahedrons with rhombic faces. Colour 

 green, of different shades. Structure fo- 

 liated ; fracture conchoidal. Specific gra- 

 vity 2-37. It is infusible. 



SO'DIUM. One of the fifty-five simple or 

 elementary bodies. Sodium is the metallic 

 basis of soda, and, like potassium, was 

 discovered by Sir H. Davy in 1807. It 

 has the appearance of silver, or of lead, 

 and is both ductile and malleable. Its 

 specific gravity is 0-97, consequently it is 

 lighter than water. 



SOIL, (sol, Fr. soulo, It.) The name given 

 to that superficial accumulation of various 

 substances which lies upon the surface of 

 the globe, and covers the rocks below ; it 

 is also called earth, mould, loam, &c. Its 

 depth is irregular, from a few inches to 

 several feet. 



SOLA'RIUM. A genus of depressed, coni- 

 cal, nearly discoidal, umbilicated, marine, 

 univalve shells, belonging to the family 

 Turbinacea. Recent solaria are littoral 

 shells, found on rocks and weeds, and be- 

 long to tropical seas. One species, sola- 

 rium canaliculatum , has been found in the 

 London clay of Hampshire : Lamarck 

 describes nine species. 



SO'LEN. A genus of marine bivalves, found 

 on sandy beaches, wherein it burrows ver- 

 tically, and lies concealed at a depth of 

 about six inches, when the tide leaves 

 the beach dry. The shell is bivalve, ob- 

 long, equivalve, inequilateral, open at 

 both ends ; hinge with a subulate reflected 

 tooth, often double, and not inserted in 

 the opposite valve. It is included in the 

 family Solenacea. 



SO'LENITE. A fossil solen. Lamarck de- 

 scribes five species, as found in the neigh- 

 bourhood of Paris. Fragments of sole- 

 nites are found in the Essex cliffs. 



SOLFATA'RA. The name of an extinct vol. 

 cano near Puzzuoli, which constantly 

 emits aqueous vapour, and sulphureous 



and muriatic exhalations. The word sol- 



fatara is now applied to any volcanic 



vent emitting sulphureous, muriatic, and 



acid vapours or gases. 

 SO'LID. A solid is that which has length, 



breadth, and thickness. 

 SOLIDU'NGULOUS. (from solidus, solid, and 



unyula, a hoof, Lat.) Having the hoof 



whole and undivided. 

 SO'HTARY. (solitarius, Lat. solitaire, Fr. 



solitario, It.) 



1. In botany, applied to peduncles when 

 there is only one on the same plant, or 

 when they stand singly in the same place ; 

 to seeds, when there is only one in a peri- 

 carp. 



2. In conchology, applied to a single tooth. 

 SO'MMITE. The name given by Jameson to 



the mineral called by Haiiy nepheline. For 

 a description of sommite, see Nepheline. 



SPAR, (spath, Germ, spath, Fr. terme de 

 miner aloffie, emprunte de VAllemand. 

 Quelques uns disent, spar.) In miner- 

 alogy, a name given to those earths which 

 easily break into rhomboidal, cubical, or 

 laminated fragments with polished sur- 

 faces. Spar constitutes the sixth order 

 of the second class in the natural history 

 system of mineralogy. Spar is not me- 

 tallic ; its streak is white, grey, brown, or 

 blue. Hardness from 3-5 to 7'0. Spe- 

 cific gravity from 2'0 to 3'7. As the 

 term spar is applied to stones of different 

 kinds, without any regard to the ingre- 

 dients of which they are composed, an 

 additional term must necessarily be em- 

 ployed to express the constituent parts as 

 well as the figure ; for instance, calca- 

 reous spar, gypseous spar, adamantine 

 spar, cubic spar, brown spar, &c. &c. 



SPA'RRY I'RON. The fei* oxide carbonate 

 of Haiiy ; spath eisenstein of Werner ; 

 fer spathique of Brongniart ; sparry iron- 

 stone of Jameson ; sparry iron-ore of 

 Kirwan. Carbonate of iron. It is of a 

 yellow, grey, brown, or black colour ; 

 occurring crystallized in rhombohedrons, 

 or in laminated and lamellar masses. It is 

 found in metalliferous veins, as well as in 

 common veins, in primary, transition, and 

 secondary rocks. It consists principally 

 of protoxide of iron and carbonic acid ; 

 some specimens yielding manganese and 

 lime ; others, magnesia, oxide of manga- 

 nese, andlime,but in very small proportions. 

 Sparry iron is a valuable ore, from the fa- 

 cility with which it may be converted into 

 excellent steel. It is, from the last cir- 

 cumstance, sometimes called steel ore. 



SPA'DIX. (spadix, Lat.) In botany, an 

 elongated receptacle : a spike, the sessile 

 flowers of which are very crowded, the 

 principal axis thick and fleshy, and en- 

 veloped in a large, coloured, bractea, is 

 termed a spadix. 



