FIG 



[173] 



PIE 



vent near to the mouth. Many 

 species have been described. 



FI'GTTRE STONE. Agalmatolite, a va- 

 riety of talc-mica, of a grey, green, 

 white, red, or brown colour. The 

 finest are brought from China. 



FI'LAMENT. ffilamenta, Lat. filament, 

 "Fi.filamtnto, It. 



1. A long thread or fibre; a slender 

 thread-like process. 



2. In botany, the long thread-like 

 part that supports the anther ; the 

 filament is not essential, being 

 sometimes wanting; the form is 

 various, being sometimes short and 

 thick, or long and slender, or 

 forked, one point only supporting 

 the anther ; generally smooth, 

 sometimes hairy ; the number 

 varies from one to many. Most 

 filaments are simple, some are 

 bifid ; others tricuspidate or broad, 

 and trifid at the extremity. 



FILAMENTOUS, (filamenteux, Fr.fila- 

 mentoso. It.) Composed of fine 

 threads or fibres. 



FILA'BIA. A genus of nematoidea, 

 belonging to the class Entozoa. 



FILE. A name given by the chalk- 

 diggers to the striated and prolonged 

 cucurmerine claviculae of echinites. 



FILI'CES. (filix, Lat.) Ferns, the first 

 order of Cryptogamia, in Linna3us's 

 artificial system ; the first tribe of 

 acotyledonous plants. In modern 

 classification, filices constitute the 

 fourth order of Acrogens. 



FILICITE. A fossil fern. 



FILICOIDE'.E. (from Mix, Lat. and 

 eiSos, Gr.) Fern-like plants. 



FI'LIFORM. (from filum, a thread, 

 and forma, form, Lat.) Thread- 

 like; thread- shaped; slender, and 

 of equal thickness. In botany, ap- 

 plied to peduncles when very fine, 

 resembling threads; applied also 

 to the tube of monopetalous flowers 

 when of a thread-like form; and 

 also to aments. 



FIN. (Sax.) The organ in fishes by 

 which they steady and keep upright 

 their bodies in the water; the cau- 



dal fin alone assists in progressive 

 motion. The fin consists of a 

 membrane supported by rays, or 

 little bony or cartilaginous ossicles. 



FIN-FOOTED. Palmipedous ; having 

 palmated feet, or feet with mem- 

 branes between the toes, connecting 

 them with each other. 



FI'ORITE. A siliceous incrustation 

 deposited by the thermal waters of 

 Ischia, first noticed by Dr. Thomp- 

 son ; called also Pearl-sinter. By 

 some mineralogists, this is con- 

 sidered to be merely a variety of 

 siliceous sinter; others constitute 

 it a distinct sub-species. It occurs 

 in stalactitical, botryoidal, globular, 

 and cylindrical masses of a milk- 

 white, yellowish -white, pearl-grey, 

 and yellowish-grey colours. It is 

 less hard than quartz, but suffi- 

 ciently hard to scratch glass. It 

 is infusible before the blow-pipe, 

 without addition. It consists of 

 silica 96, or, according to some, 

 94, alumina 2, lime 4. It is re- 

 garded by some authors as a vol- 

 canic product. 



FIRE-DAMP. Choke-damp. Carbu- 

 retted hydrogen gas. This is some- 

 times very abundantly evolved in 

 coal mines, and is productive of the 

 most dreadful results, occasionally 

 nearly all employed in the mines 

 perishing from its combustion. 

 When carburetted hydrogen gas 

 constitutes more than one-thir- 

 teenth of the volume of the atmos- 

 phere of pits and mines, the whole 

 become explosive whenever a flame 

 is brought into contact with it ; to 

 prevent the disastrous consequences 

 which were so frequently resulting, 

 Sir H. Davy invented a safety-lamp, 

 which being formed of wire-gauze, 

 in the form of a cylinder, consumes, 

 but does not explode, the explosive 

 mixture. It has been well and 

 truly observed, "if the genius of 

 Davy had merely produced his 

 safety-lamp, it would alone have 

 entitled him to the applause and 



