FLU 



[ 179] 



F OL 



structive properties it has been 

 called phtore, from (fredpio?, Gr., 

 by M. Ampere. It destroys the 

 skin, almost immediately, if applied 

 to it, producing very painful 

 wounds. The most singular pro- 

 perty which it possesses is that of 

 corroding glass and siliceous bodies, 

 especially when hot, and the thick- 

 est glass vessel can only withstand 

 its action for a short time. 



Fluorine enters into the compo- 

 sition 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 com- 

 ponent parts of many rocks. 

 Fifteen analyses of mica, from 

 various parts of the world, by 

 Klaproth, Vauquelin, Kose, and 

 Bendant, afford as a mean, 1*09 

 per cent, of fluoric acid; and 

 Bousdorf s analysis of hornblende, 

 gives 1.5 per cent, of the same 

 substance. Calculation affords us 

 0*36 of fluoric acid in gneiss with 

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

 cent, in hornblende rock and green- 

 stone, 0'18 in granite with mica, 

 0'5 of the same substance in 

 sienite, 0*5 per cent, in porphy- 

 ritic greenstone. Fluor spar is, 

 however, the mineral in which the 

 greatest relative amount of fluorine 

 is detected. De la Beche. The 

 symbol of fluorine is F. 

 FLI/STRA. A genus of polyparia, 

 class Vermes, order Zoophyta. If 

 we carefully observe the patches of 

 white calcareous matter, called 

 flustrse, that may be seen on every 

 sea-weed or shell on the shore, 

 appearing like delicate lace, we 

 shall discover that these apparently 

 mere specks of earthy substance 

 belong to the animal kingdom. 

 The flustra, when taken fresh and 

 alive out of the water, presents to 

 the naked eye the appearance of 

 fine network, coated over with a 

 glossy varnish. "With a glass of 



moderate powers, it is discovered 

 to be full of pores, disposed with 

 much regularity. If a powerful 

 lens be employed, while the flustra 

 is immersed in sea- water, very 

 different phenomena appear; the 

 surface is seen to be invested with 

 a fleshy, or gelatinous, substance, 

 and every pore to be the opening 

 of a cell or cavity, whence issues 

 a tube with several long feelers or 

 tentacula ; these expand, then sud- 

 denly close, withdraw into the cells, 

 and again issue forth; and the whole 

 surface of the fiustra is studded with 

 these hydra-like forms, sporting 

 about in all the energy and activity 

 of life. For a more full account, 

 see Dr. Mantell's Wonders of Geo- 

 logy, whence the above is taken. 

 FLUX, (jluxus, Lat. flux, Fr. mouve- 

 ment regU de la mer vers U rwage d 

 certaines heures dujour.J 



1. The flow of the tidal wave : the 

 flux is the rise; the reflux, the 

 ebb of the tide. 



2. Any substance added to facilitate 

 the fusion of metals or minerals. 



F(E'CAL, See Fecal. 

 FCE'CES. See Feces. 

 FO'LIATED. (foliatus, Lat.) 



1. In botany, leaved or having 

 leaves. 



2. In conchology, in laminae or 

 ] eaves, as when the edges of the 

 shelly layers are not compact, but 

 seem to separate from each other. 

 This may easily be seen in the large 

 coarse oyster shell. 



3. In mineralogy, the term foliated 

 was used by Werner to express 

 the structure of such minerals as 

 may be divided or cleaved regularly, 

 and were therefore said by him to 

 consist of folia or leaves. 



FOLIA'TION. 



1. In botany, vernation or leafing 

 of trees, &c. 



2. In mineralogy, the act of beating 

 into thin leaves. 



3. Mr. Darwin proposes to give the 

 term foliation to the tendency in 



