LI M 



LIN 



vessels, it yields pyro-ligneous acid ; and 

 a peculiar spirituous liquor is produced, 

 called pyro-xylic spirit. 



LIGNIPE'RDOUS {lignum, wood, 

 per do, to destroy). A term applied to 

 insects which destroy wood. 



LI'GNITE {lignum, wood). A variety 

 of coal, of a brown, dull, compact, or 

 laminated appearance, often woody, burn- 

 ing A*ith flame and smoke. 



LI'GNONE {lignum, wood). Xylite. 

 A liquid which exists in commercial 

 pyroxylic spirit, — a product of the dis- 

 tillation of wood. 



LI'GNUM. Wood; that portion of 

 arborescent plants which comprises the 

 alburnum and the duramen. 



LI'GULA. A peculiar membranous 

 process at the top of the sheath in grasses, 

 between the sheath and the blade. 



LFGULATE FLOWERS {ligula, a 

 strap). Strap-shaped flowers, or those 

 which have a gamopetalous corolla slit on 

 one side, and opened flat, as in many of 

 the composite plants. 



LI'GURITE. A silicate of alumina, 

 lime, and magnesia, found in a talcose 

 rock on the banks of the Stura in the 

 Apennines. It is reckoned superior to 

 the chrysolite as a gem, in colour, hard- 

 ness, and transparency. 



LILIA'CEiE. The Lily tribe of Mo- 

 nocotyledonous plants. Bulbous, tuber- 

 ous, creeping, or arborescent plants; 

 calyx and corolla inferior, coloured, regu- 

 lar ; stamens 6 ; anthers opening in- 

 ward ; fruit 3-celled. 



LILY ENCRINITE. A radiated ani- 

 mal occurring in the seas of the new red 

 sandstone, enclosed within a stony habi- 

 tation, said to consist of nearly thirty 

 thousand separate pieces, and planted 

 upon a stony but moveable column, 

 nearly cylindrical, and attached at its 

 base to the solid rock. See Encrinites. 



LIMACI'NiE. Slugs ; a sub-family of 

 the Helicidce, named from the genus 

 Umax, and having either no shell, or one 

 much too small to contain the body. 



LIMB. A term applied to the curved 

 edge of a circle, as the graduated limb of 

 a quadrant. In Astronomy, it denotes 

 the outermost border of the sun or moon ; 

 thus, it is usual to speak of the moon's 

 lower or upper limb, and even of her 

 eastern or western limb ; and especially, 

 in the case of an eclipse, when a portion 

 of her disc is obscured. 



LI'MBILITE. A compact mineral, 

 found in the form of irregular grains in 

 the volcanic hill of Limbourg. 

 198 



LIME. The oxide of calcium ; an al- 

 kaline earth, found as a carbonate in 

 marble, chalk, and limestone. These 

 substances become lime, when burned in 

 a white heat. Quick lime is limestone 

 which has been burned, and acquired 

 new properties. Slaked lime is the pow- 

 der produced by pouring water upon 

 quicklime ; this is a hydrate, and, when 

 diff"used through water, yields the sub- 

 stance called milk or cream of lime. 



LIMESTONE. A designation of the 

 various modifications of calcareous rocks, 

 consisting of carbonate of lime. The 

 principal kinds are the primary or crys- 

 talline, the secondary or compact, the 

 oolite, chalk, &c. Saccharine limestone 

 is a term applied to a few small beds oc- 

 curring in the inferior stratified series of 

 rocks, from its resemblance to refined 

 sugar; it is sometimes called primitive 

 limestone, from the period of its occur- 

 rence in this series. 



LIMIT {limito, to bound). A bound- 

 ary. But the term limit is employed in 

 the sciences in a wider sense. There are 

 certain eflTects in Natural Philosophy, as 

 well as quantities in Mathematics, which 

 cannot be determined with accuracy; 

 but, in many of these cases, we may fix 

 dk point which that effect or quantity va.\xst 

 certainly exceed, and another at which 

 it cannot possibly arrive. These points 

 are the limits of the problem. Thus, 



1 . We cannot predict the exact height 

 at which the mercury will stand, at the 

 level of the sea, in a barometer, on any 

 future day; but we may assert, from 

 past e-perience, that it will be some- 

 where between twenty-eight and thirty- 

 one inches. So also, 



2. We cannot determine exactly the 

 length of the circumference of a circle ; 

 but we are certain that it is greater than 

 that of any inscribed polygon, and less 

 than that of any circumscribed one, how- 

 ever numerous their sides may be. 



LIMNACI'N./E. River-snails ; a sub- 

 family of the Helicince, named from the 

 genus limnea, and having only two de- 

 pressed or flattened tentacula, and no 

 operculum. 



LIMNiE'IDiE {\ifjivv, a marsh). A 

 family of fresh-water testaceous mol- 

 lusca, consisting of the genera limncea, 

 physa, and planorbis. Lamarck defines 

 them as amphibian trachelipods, gene- 

 rally inoperculate, with flattened tenta- 

 cula, and a spirivalve shell. 



LINA'CEiE. The Flax tribe of dico- 

 tyledonous plants. Herbaceous plants, 



