L AT 



LAY 





LAPIDIFICA'TION {lapis, a stone, 

 fio, to become). The process of conver- 

 sion into stone. 



LAPI'LLI {lapillus, dim, of lapis, a 

 stone). Small stones ; small volcanic 

 cinders. 



Lapis, a generic term, signifying 

 all kinds of stone : thus, lapis calcareus 

 is limestone ; lapis infernalis is an old 

 term for caustic potash; lapis calami- 

 naris is the impure carbonate of zinc ; 

 lapis comensis is potstone, an intimate 

 mixture of talc and asbest ; lapis lazuli 

 is a zinc-stone, from which ultra-marine 

 is prepared, &c. 



LA'RBOARD. By a person standing 



at the stern of a ship, and looking 



towards the prow, the left-hand side is 



\M^ &lMI^ termed the larboard, and the right-hand 



-.^ ^|^*side the starboard. 



fj^ff%> * LA'RIDiE {larus, the sea-gull). The 



w _^^^ ^ull tribe ; a family of the Natatores, or 



^^^ Swimming birds, including the gull, the 



petrel, the albatross, &c., in which the 



powers of flight are considerable, while 



those of swimming and diving are 



defective. 



LA'RVA (Lat., a mask). A caterpil- 

 lar ; the earliest state of insect existence, 

 so named by Linnaeus because in this 

 condition the perfect form of the insect 

 is concealed, as it were, under a mask. 

 The term larva is applied to the grub, 

 the caterpillar, and the maggot. See 

 Pupa. 



LARVI'PAROUS {larva, and pario, 

 to produce). A designation of those in- 

 sects which produce their young in the 

 condition of larvae. 



LA'SIONITE. A phosphate of alumina 

 from Amberg in Bavaria. It is a variety 

 of hydrarfiyllite. 



LATE'BRICOLiE {latebra, a hiding- 

 place, colo, to inhabit). A family of 

 Spiders, which hide themselves in bur- 

 rows and fissures, which they line with 

 a web. 



LATENT HEAT. That quantity of 

 heat which is absorbed during the con- 

 version of a solid into a liquid, or of a 

 liquid into a vapour, without raising the 

 temperature in the least degree. See 

 Caloric. 



LA'TERAL {latus, lateris, the side). 

 Belonging to the sides of a body. Thus, 

 the lateral teeth of bivalves, where they 

 exist, are on one or both sides of the 

 cardinal teeth, which are always central. 



LATERI'GRADA {latus, lateris, the 

 side, gradior, to advance). A family of 

 Spiders, which make no web, but run, 

 192 



crab-like, sideways or backwards, and 

 occasionally throw out adhesive threads 

 to entrap their prey. 



LATEX {lateo, to be hidden). Any 

 kind of liquor squeezed out. This term 

 denotes, in Botany, a highly elaborated 

 and highly organized juice, which is not 

 formed immediately from the fluid matter 

 absorbed from without. The tissue, in 

 which this juice is found, is termed lati- 

 ciferous tissue, and more recently cinen- 

 chyma. 



LATITUDE {latitudo, breadth). The 

 latitude of a place on the earth's surface 

 is its angular distance from the equator, 

 measured on its own terrestrial meri- 

 dian ; it is reckoned in degrees, minutes, 

 and seconds, from up to 90°, and north- 

 wards 05 southwards according to the 

 ■hemisphere in which the place lies. Thus 

 the observatory at Greenwich is situated 

 in 51° 28' 40" north latitude. 



1. Latitude, parallels of . Small circles 

 on the earth's surface parallel to the 

 equator. Every point in such a circle 

 has the sam.e latitude. Thus, Greenwich 

 is said to be situated in the parallel of 

 51° 28' 40". 



2. Latitude of a star. The distance of 

 a star from the ecliptic, measured on the 

 great circle passing through the star and 

 the pole of the ecliptic. 



LA'TROBITE. A pink-coloured mine- 

 ral, allied to felspar, found in Amitok 

 island, near the coast of Labrador, and 

 named from Mr. Latrobe. 



LAUMONTITE. Lomonite. A zeo- 

 litic substance, named from Gillet-Lau- 

 mont. It is also called efflorescent zeo- 

 lite, because some of its varieties are sub- 

 ject to decomposition on exposure to the 

 air. 



LAURACE.E. The Cinnamon tribe 

 of Dicotyledonous plants. Leaves entire, 

 alternate ; flowers apetalous ; stamens 

 perigyn'ous ; fruit baccate or drupaceous ; 

 seeds without albumen. 



LAURINE. An acrid and bitter prin- 

 ciple contained in the berry of the laurel. 



LA'VA. A general term for the sub- 

 stances emitted from volcanoes, in a 

 fused or fluid state. In its ordinary con- 

 dition, it differs from basalt chiefly in 

 being porous. It admits, however, of 

 several varieties, which are sufficiently 

 characterized by the terms compact, vesi- 

 cular, slaggy, and spumous. 



LAYERING. The process of propa- 

 gating young plants from a parent stock, 

 by laying down a branch, and then sepa- 

 rating it from its parent. See Malleolus, 



