SOL 



SOL 



tion of a more fusible metal, which, 

 being melted upon each surface, serves, 

 partly by chemical attraction, and partly 

 by cohesive force, to bind them together. 

 See Solder. 



Soldering, autogenous. This process 

 consists in the union of two pieces of 

 metal without the interposition of any 

 solder, by fusing them at the point of 

 junction by jets of flame from a gas 

 blow-pipe. 



SOLENI'N^. The Solens; a sub- 

 family of the Myadae, or Gaping bi- 

 valves, named from the genus solen, and 

 having their shells always open at both 

 extremities. 



SO'LENOID {<Tuy\riv, a channel, a cy- 

 lindrical box, ei3o9, likeness). The name 

 given by Ampere to what is otherwise 

 called an electro-dynamical screw, or elec- 

 tro-dynamical cylinder. It consists of a 

 linear series of circular currents passing 

 at right angles to the axis of the spiral 

 conductor. 



SOLFATA'RA. A volcanic vent from 

 which sulphur, sulphureous, watery, and 

 acid vapours and gases are emitted. The 

 name is derived from Solfaterra, the cele- 

 brated mountain of Naples, called by the 

 ancients Phlegrcei campi. 



SOLID. In geometry, a solid figure is 

 one enclosed by, at least, four planes or 

 faces, and named from the number of its 

 faces ; thus a figure with four faces is 

 called a tetrahedron ; one with six, a 

 hexahedron; those with more than six, 

 polyhedrons. Solids are also named ac- 

 cording to the figures and positions of 

 their faces, as the prism, the parallelo- 

 piped, &c. 



1. Solid dimension. Length is said to 

 be a quantity of one dimension, surface 

 of two, and solidity of three, viz. length, 

 breadth, aud thickness. The right line, 

 the right surface or rectangle, and the 

 right solid or rectangular parallelopiped 

 are the implements of mensuration. 



2. Solid of least resistance. A term 

 applied to a geometrical solid of such a 

 shape as will enable it to move with the 

 least resistance through the air, water, 

 or other fluid. Such a solid is a conoid. 



3. Solids', regular. A regular solid is 

 one whose faces are equal, equilateral, 

 and equiangular plane figures. There 

 are, but cannot be more than, five regu- 

 lar solids ; three of these have triangular 

 faces, one square faces, and the remain- 

 ing one pentagonal faces. 



4. Solid problem. A soiid, as distin- 

 guished from a plane, problem, in geo- 



307 



metry, is one which cannot be con- 

 structed by the intersections of circles 

 and straight lines, but requires for its 

 construction the description of one or 

 more conic sections. 



SOLID (in Physics). A term denoting 

 that constitution of matter in which the 

 attractive forces of the molecules are 

 greater than the repulsive, and the 

 molecules consequently cohere with more 

 or less force. In the liquid state, the 

 two forces are balanced ; in the gaseous 

 the repulsive predominates. 



SOLIDIFICATION. The condition 

 exactly opposed to liquefaction; it is 

 the state assumed by liquid bodies on 

 parting with their free caloric. With- 

 out adhering strictly to this rule, we 

 generally use the term solidification, when 

 we speak of such fluids as become solid 

 at a temperature higher than that of 

 freezing water; and freezing, when we 

 speak of such as become solid at a point 

 below 32°. 



SOLIDU'NGULA {sola ungula, a sin- 

 gle hoof). Solipeds. A group of pachy- 

 dermatous animals, comprising quadru- 

 peds with only one apparent toe, and a 

 single hoof to each foot, as the horse. 



SOLITA'RIUS. The Hermit ; an ob- 

 scure cons ellation of Lemonnier, situ- 

 ated a little above Centaurus, near the 

 tail of Hydra. 



SO'LSTICES {sol, the sun, sto, to 

 stand). The two extreme points of the 

 Sun's apparent course north and south 

 of the equator. These are the first points 

 of Cancer and of Capricorn, where the 

 sun appears to make a stand, going nei- 

 ther northward nor southward. The two 

 corresponding periods of the year are 

 called the Summer and the Winter sol- 

 stices, from the seasons in which the 

 apparent standings of the sun occur. 



SOLUBFLITY. A contrivance of 

 nature for facilitating the dispersion of 

 seeds in some plants. It arises from the 

 presence of certain transverse contrac- 

 tions of a 1-celled pericarp, through 

 which it finally separates into several 

 closed portions, as in ornithopus, entada, 

 &c. 



SOLUTION {solve, to dissolve). The 

 operation of dissolving a solid or aeri- 

 form body in a liquid. The condition of 

 the solid or aeriform body is called its 

 solution ; the liquid which eflects the 

 change is the solvent. When the liquid 

 will dissolve no more of the solid, but 

 allows the excess to be deposited on the 

 bottom of the vessel, it is said to be satu-^ 



