F L I 



[ 98] 



FLU 



principle of chemical affinity, have a ten- 

 dency to attach itself. The chalk and 

 flint proceeded through a contemporaneous 

 process of consolidation ; the separation 

 of the siliceous from the calcareous in- 

 gredients having been modified by at- 

 tractions, which drew to certain centres 

 the particles of the siliceous nodules, as 

 they were in the act of separation from 

 the original compound mass. The dis- 

 tances of the siliceous strata must have 

 been regulated by the intervals of pre- 

 cipitation of the matter from which they 

 are derived ; each new mass, as it was 

 discharged, forming a bed of pulpy fluid 

 at the bottom of their existing ocean, 

 which, being more recent than the bed 

 produced by the last preceding precipitate, 

 would rest upon it as a foundation similar 

 in substance to itself, but of which the 

 consolidation was sufficiently advanced to 

 prevent the ingredients of the last de- 

 posit, from penetrating or disturbing the 

 productions of that which preceded it." 

 Sir. H. Davy found pure flint in the 

 cuticle of many grasses ; it is also found 

 in the hollow stems of bamboo ; the ashes 

 of wheat straw also are found to contain it. 



FLI'NTY SLATE. Flinty slate differs from 

 common slate, in containing a larger pro- 

 portion of siliceous earth. Slate and 

 flinty slate not only pass into each other, 

 but frequently alternate. When flinty 

 slate ceases to have the slaty structure, it 

 becomes hornstone, or, what the French 

 geologists term petrosilex. If it contains 

 crystals of felspar, it becomes hornstone 

 porphyry. Bakewell. 



FLO'ATSTONE. The white and grey porous 

 varieties of rhombohedral quartz. In 

 consequence of their extreme porousness 

 they swim on the surface of water, and 

 have therefrom been named floatstone, or 

 spongiform quartz. 



FLOETZ. (flotz, Germ.) The name given 

 by Werner to certain rocks which were 

 flat, horizontal, and parallel to each 

 other. 



FLO'RA. (Lat.) As the animals peculiar 

 to any country constitute its fauna, so 

 do the trees and plants its flora ; the 

 botany of a country. 



FLO'RAL. (floralis, Lat.) An epithet for 

 a bud or leaf; pertaining to flowers ; be- 

 longing to the flower. The calyx is the 

 outer set of the floral envelopes. 



FLO'RET. (jleurette, petite fleur, Fr.) A 

 floret is a small monopetalous flower, 

 many of which, enclosed in one calyx or 

 perianthium, and placed sessile on a com- 

 mon undivided receptacle, form a species 

 of compound flower. 



FLORI'FEROUS. (florifer, Lat.) Bearing 

 flowers ; producing flowers. 



FLO'RIFORM. (from flos and forma, Lat.) 



Having the form, or appearance, of a 

 flower. 



FLO'SCULOUS. (flosculus, Lat.) A little 

 flower ; a floret. 



FJLU'ATE. A compound of fluoric acid 

 with a salifiable base. 



FLU'CAN. A provincial name for a fault or 

 dam ; particularly used by the Cornish 

 miners. 



FLU'OR. ) (Lat.) Octahedral fluor. 



FLU'OR SPAR. $ Octaedrisches Flus-Ha- 

 loide of Mohs. Chaux Fluate of Haiiy. 

 Fluate of lime ; consisting of 67' 75 lime 

 and 32-25 fluoric acid. If a cube of fluor 

 spar be split with a knife and a hammer, 

 it will yield only in the direction of the 

 solid angles, and if the division be pur- 

 sued the result will be an octohedron. 

 There are three varieties of fluor spar ; 

 the first, with even fracture and feeble 

 lustre, is called compact fluor ; the second, 

 in which the cleavage is distinct, foliated 

 fluor ; the third, which occurs incrusting 

 other minerals, earthy fluor. See also 

 Blue-John and Derbyshire spar. 



FLUO'RIC ACID. An acid first procured by 

 Gay Lussac, or by Margraff, and called 

 fluorine by Sir H. Davy. It may.be ob- 

 tained by putting a quantity of fluor-spar 

 in powder into a leaden retort, pouring 

 over it an equal quantity of sulphuric 

 acid, and then applying a very gentle 

 heat. From its exceedingly destructive 

 properties it has been called phtore, from 

 00optoc, Gr., by M. Ampere. It destroys 

 the skin, almost immediately, if applied 

 to it, producing very painful wounds. 

 The most singular property- which it pos- 

 sesses is that of corroding glass and 

 siliceous bodies, especially when hot, and 

 the thickest glass vessel can only with- 

 stand its action for a short time. 



Fluorine enters into the composition of 

 some minerals which form constituent 

 portions of great masses of rocks. Fluoric 

 acid is found in mica and hornblende, 

 two minerals of very great importance, as 

 component parts of many rocks. Fifteen 

 analyses of mica, from various parts of 

 the world, by Klaproth, Vauquelin, Rose, 

 and Bendant, afford as a mean, T09 per 

 cent, of fluoric acid ; and Bousdorf's 

 analysis of hornblende, gives 1*5 per cent, 

 of the same substance. Calculation af- 

 fords us 0'36 of fluoric acid in gneiss with 

 mica, 0'54 in mica slate, 0'75 per cent, 

 in hornblende rock and greenstone, 0-18 

 in granite with mica, 0*5 of the same 

 substance in sienite, 0'65 in granite com- 

 posed of quartz, felspar, mica, and horn- 

 blende, and 0'5 per cent, in porphyritic 

 greenstone. Fluor spar is, however, the 

 mineral in which the greatest relative 

 amount of fluorine is detected. De la 

 Beche. 



