FLTTIDACIA 



131 



FOIL 



Fluidacia, (flu-i-da'si-a). [Fluid, q.v.] v. 

 Damortier. 



Tluke, (fluk)=Flounder, q.v. F. worm, v. 

 Trematoda. v. Cercaria. 



Tluo, (flu'o). [Fluorine, q.v.] A prefix: ex- 

 pressing the presence of fluorine. 



Fluo-boric acid, (nu-o-bo'rik). [Fluorine and 

 Boron, q.v.] B 2 3 .6HF=Boro-fluoric : a 

 solution of boro-fluoride in water; an oily 

 corrosive liquid. 



Fluocerine. (flu'o-ser-in). [Fluo and Cerium, 

 q.v.] A mineral, chiefly cerium and fluorine. 



Fluocerite, (flu'o-ser-it). [Fluo and Cerurn, 

 q.v.] A haliod mineral of the fluorite group, 

 chiefly cerium and fluorine. 



Fluochlore, [flQ'o-klor). [Fluo and Chlorine, 

 q.v.]=Pyrochlore, q.v. 



Fluor, (flu'or). [L. fluo, I flow. ]= Fluor-spar. 

 F. apatite : a variety of apatite. F. spar= 

 Calcic fluoride=CaF 2 : the only commonly 

 found native compound of fluorine; also 

 called Fluor, Fluorite, and Derbyshire spar. 



Fluorene, ( fliYo-ren ). [Fluorine, q.v.] = 

 CisHjo : a hydrocarbon obtained from coal 

 tar. 



Fluorescein, (flu-o-res'In).=C2oHi2O 5 : a crys- 

 talline substance obtained from resorcin ; 

 named from becoming fluorescent when dis- 

 solved in ammonia. 



Fluorescence, (flil-6-res'ans). [Fluor, q.v.] 

 The property of some usually invisible rays 

 of a spectrum to become visible when their 

 rates of vibration are altered. Ex. If a screen 

 receiving a solar spectrum be soaked in solu- 

 tion of ajsculine, the spectrum is lengthened, 

 moi m e rays becoming visible: caused by flour- 

 spar, and other substances which reduce the 

 vibrations of invisible rays, so as to make 

 them visible. 



Fluorhydric acid, (flu-or-hi'drik). [Fluorine 

 and Hydrogen, 5.v.]=HF=Hydrogen fluoride 

 = Hydrofluoric acid, q.v. 



Fluorides, (flu'6-ridz). [Fluorine, q.v.} Com- 

 pounds of fluorine and a metaL 



Fluorine, (flu'6-rm or flu'o-ren). [Fluo, to 



, flo\v.]=rF': a colourless gas, obtained separate 

 with difficulty, one of the Halogens, q.v. 



Fluorite, (flu'6-rit). [Fluor, 2.v.]=Fluor: a 

 mineral, chiefly fluoride. F. group of 

 minerals: includes fluorite, fluocerite, cryo- 

 lite, and yttrocerite. 



Flustra, (flus'tra). Sea-mat : a compound 

 animal belonging to Polyzoa, consisting of 

 minute animals livingin aggregations; named 

 from their mat-like appearance. 



Flustridae, (flus'tri-de). [Flustra, q.v.]=Sea.- 

 mats: a family of Polyzoa, of which Flustra 

 is the type. 



Fluvio marine, (Flft'vi-o ma-ren'). [L. fluvius, 

 river; mare, sea. ] Related to both river and 

 sea. F. strata: brought to the sea by the 

 action of rivers. 



Fluviales, (flfi'vi-a-lez). [L. fluvius, river.] 

 =Naiadacefe, q.v. 



Flux, (fluks). [L. fluo, flow.] A substance 

 used in smelting to form fusible compounds 

 with the earthy matters found in the ores. 

 Black F. = Potassic carbonate and carbon. 

 White jP.zrPotassic carbonate and nitre, 



Fluxions, (fluk-shunz). [L. fluo, I flow.]= 

 Differential calculus, q.v. 



Fly,(fli). [Fleoge, the A.-S. name.l=Musca: 

 an insect belonging to Diptera. mistering 

 .F.=Cantharis. Boat .F.=Notonecta. Sot 

 F. = (Estrus equi. Suiter F. = Papilio. 

 Caddis F. =Phryganea. Crane .F. =Tipula. 

 Day F.= Ephemera. Dragon F. =Libellula. 

 Fire F.=Lampyra. Flesh F.^Musca car- 

 naria. Gad J'.=(Estrus. Gall F. =Cynips. 

 Golden .F.=Chrysi8. Harvest .F.:=Cicadia. 

 Horse .F.=Hippobosca. Lantern J^.^Ful- 

 gora. Saw F. = Teuthredo. F. catchers 

 Muscicapa. F. fungus=Emp\iaa. muscas. F. 

 wheel, I. Wheel. F. 

 bug = Reduvius per- 

 sonatus : an insect, be- 

 longing to Heteroptera, 

 which devours the bed- 

 bug. 



Flying. F. birds=Ca.ri- 

 natee. F. bridge = a 

 boat moved to a buoy, 

 so that the current 

 moves it across a river. 

 F. buttress, v. Buttress. 

 F. dragon=Dr&co volans: a small Indian 

 lizard. f.j?s/t=Exocsetus. F . /oz=Pteropus. 

 F. frog = Rhacop- 

 horua ; has large' 

 webbed feet with 

 adhesive discs. F- 

 gurnard = Dacty- 

 lopterus. F, lemur 

 = Galeopithecus. 

 F. lizard = Ptero- 

 saur ia. F. squirrel, 

 v. Squirrel. 



Focal distance, (foTcal). 



Flying-buttress. 



Flying-flsh. 

 [Focus, q.v.] 



The 



distance of the focus from a mirror. 



Foci, (fo'si). Plural of Focus. Calorific P.: 

 focus of heat rays. Luminous P.: focus of 

 light rays. Acoustic P.: focus of sound rays. 



Focus, (fo'kus). [The Latin word.] Point of 

 concentration. Real F. ; formed in front of 

 a mirror by reflected converging rays of light. 

 Virtual F.: apparently formed behind a 

 mirror. Conjugate P., v. Spherical mirror. 



Fosniculum, (fe-nik'u-lum). [The Latin name.] 

 =Fennel: an herb belonging to Urn belli ferae. 



Foetal, (fe'tal). [Foetus, q.v.] Related to a 

 foetus. F. cotyledons, v. Cotyledon. F. 

 life: the period of life during which the 

 individual exists in the foetal state. 



Foetus, (fe'tus). [The Latin name.] The 

 young of vertebrate animals between the 

 embryo and independent states; the per- 

 fected embryo during the period previous to 

 its separation from the parent. 



Fog, (fog). [Fok, the Icelandic word.] A 

 visible vapour floating in the air, near the 

 surface of the earth. F. signals : usually by 

 means of sound, to 

 give notice of danger 

 in case of fog. 



Foil, (foil). [L. folium, 

 leaf.] 1. Very thin 

 sheets of metal. 2. A Foils. (Arch.) 

 rounded or leaf-like ornament in tracery. 



