LIN 



LIT 



with leaves usually alternate ; flowers sym- 

 metrical, polypetalous ; stamens hypo- 

 gynous ; ovarium entire, many-celled; 

 seeds compressed and inverted. 



LINE. Euclid defines a mathematical 

 line as that which has " length without 

 breadth." This, however, is a pure ab- 

 straction, and can be only mentally con- 

 ceived by the aid of another abstraction : 

 thus, if a mathematical point be imagined 

 to move in space, and to mark its course 

 by a trace or track, this trace or track 

 will be a mathematical line. Such a line 

 is the boundary of a surface, having 

 length only. A right line, or straight 

 line, is that which lies evenly between 

 its extreme points. Any line of which 

 no part is a right line, is called a curve. 



LINEAR EQUATION. An equation 

 of the first degree ; in other words, an 

 equation connected with straight lines. 



LINNtE'AN system, a method of 

 classifying plants, introduced by Lin- 

 naeus, and founded on modifications of 

 the sexual apparatus. See Botany. 



LIPS OF SHELLS. The two sides of 

 the aperture of spiral shells are termed 

 the lips. That which joins, and gene- 

 rally folds over, the lower part of the 

 columella, is called the inner lip, while 

 that part of the circumference which is 

 opposite is the outer. The latter, of 

 course, is found in all shells, because it 

 is the termination of the last whorl ; but 

 the former is frequently absent, or indi- 

 cated merely by a thin, whitish, almost 

 transparent enamel. 



LIQUA'TION {liquo, to melt). Eli- 

 quation. An old process for separating 

 silver from copper. During reduction, 

 the silver is mixed with lead, which has 

 little affinity for the copper, but combines 

 readily with the silver ; the lead is then 

 separated from the silver by cupellation. 



LIQUEFACTION {liquefacio, to melt). 

 The passing of a substance from the solid 

 to the liquid state— one of the effects of 

 caloric. The term is sometimes syno- 

 nymous with fusion, with deliquescence, 

 and with solution. 



LIQUID {liqueo, to melt). An ine- 

 lastic fluid, the particles of which move 

 on each other, and yield to the slightest 

 impression. All liquids may be arranged 

 into two great classes, viz. simple liquids, 

 as mercury, and compound liquids, as 

 combined gases, &c. 



LI'THARGE (\/6>o?, a stone, ap7upor, 

 silver). A semi-crystalline protoxide of 

 lead, obtained in the process of sepa- 

 rating silver from lead ores. Litharge 

 199 



is more or less white or red according to 

 the metals with which the silver is al- 

 loyed, the white being called litharge of 

 silver, the red litharge of gold. 



LI'THIA (\i'6>of, a stone). The pro- 

 toxide of lithium; an alkaline oxide 

 existing in certain minerals, and in the 

 waters of Carlsbad, in combination. Its 

 name is derived from its occurring only 

 in the mineral kingdom. 



LITHIC ACID (At6^or, a stone). Uric 

 acid. A principle constantly present in 

 healthy urine, and generated by the 

 action of the kidneys. 



LI'THIUM {XiOoi, a stone). A metal 

 first found in the minerals petalite and 

 spodumene, and more recently in ambly- 

 gonite and lepidolite, where it exists in 

 combination with silica. 



LITPIO'DOMI (XiOo^, a stone, hepaa, 

 to build). Molluscous animals which 

 form holes in solid rocks, in which they 

 lodge themselves. The holes are not 

 perforated mechanically, but the rock 

 appears to be dissolved. 



LITHO'GENOUS (A/^or, a stone, 7€v- 

 vd<a, to form). A term applied to polyps 

 which form coral. 



LITHOGRAPHIC STONE (\i'6/o9, a 

 stone, 7pa0ft), to write). A slaty com- 

 pact limestone, of a yellowish colour and 

 fine grain, used in lithography. 



LITHOI'DAL {Kieoi, a stone, elbo^, 

 likeness). Having a structure resembling 

 stone. 



LITHOLO'GICAL {KiBoi, a stone, X6- 

 70f, an account). A term denoting the 

 stony structure or character of a mineral 

 mass. The lithological character of a 

 stratum is distinguished, in the language 

 of geology, from its zoological character. 



LI'THOMARGE. Steinmarck. Stone- 

 marrow, a mineral which has been asso- 

 ciated with steatite, although most of its 

 varieties are silicates of alumina ; the 

 more remarkable of which are, that of a 

 reddish-yellow colour in porphyry, from 

 Rochlitz, and the fine purplish-blue va- 

 riety from Planitz, formerly called terra 

 miraculosa Saxonica, &c. 



LITHO'PHAGI {\ieoi, a stone, (pdfui, 

 to eat). Molluscous animals which form 

 holes in solid stones. See Lithodomi. 



LITHOPHA'GIDiE {\i9o^, a stone, 

 0«7a), to eat). A general designation of 

 those conchiferous and other animals, 

 which perforate stones or corals, forming 

 therein a nidus, or shallow basin-like 

 lodgment for themselves. 



LITHO'PHYTA (Xt^op, a stone, ^vrot/, 

 a plant). A designation of those polyps 

 K4 



