FLU 



835 



FLY 



other and easily separated, are held to- 

 gether by a feeble cohesion ; and elastic 

 fluids, gases, or aeriform fluids, between 

 the particles of which there is a certain 

 degree of repulsion, and which, when 

 unconfined, tend to diffuse themselves 

 through space. The property of fluid bo- 

 dies, by which they yield to any force 

 impressed, is ca\]e A fluidity. 

 FLUKE, from Germ.pflug, a plough. 1. The 

 broad part of an anchor, which takes hold 

 of the ground. 2. A fish, the plaice. 



FLUOBOR'IC ACID, a gaseous acid ob- 

 tained by heating in a retort 12 sulphuric 

 acid with a mixture of 1 fused boracic 

 acid and 2 fluor spar. 



FLU'ORIC ACID. The substance described 

 by Gay-Lussac, Margraff, and others, 

 under this name, is now considered a com- 

 pound of hydrogen and fluorine, and 

 hence is called hydrofluoric acid (q. v.). 



FLC'ORIDE, a compound of fluorine and 

 a metal, asfluor par, which is a fluoride 

 of calcium. 



FLU'ORINE, an elementary body, which 

 has not hitherto been obtained in sufficient 

 quantity, in an insulated state, for exa- 

 mination. It forms the basis of hydro- 

 fluoric acid, and exists in nature as a com- 

 ponent of a few minerals, of which fluor 

 spar is the most common. 



FLU'OR SPAR, a native fluoride of cal- 

 cium, thus named from fluo, to flow, 

 because used as a flux for metals. The 

 coloured specimens are popularly known 

 under the name of Derbyshire spar. It 

 crystallises in the cubic system, with re- 

 gular octahedral and tetrahedral cleava- 

 ges. Sp.gr. 3-198. 



FLUOSILIC'IC ACID, a binary compound 

 of silicon and fluorine. It is a colourless 

 gas; 100 cubic inches weigh 112 grs. 



FLUSH. 1. A term in a game at cards, 

 where they are all of a suit. 2. A join- 

 er's term to denote the continuity of two 

 or more parts to the same surface. 



FLUSH AND BEAD. See BEAD AND FLUSH. 



FLUSH DECK, a deck without a half- 

 deck or forecastle. 



FLDS'TRA, the sea-mat. A genus of zoo- 

 resembling themillepores, the cells 

 ig inhabited by polypi. The flustrae 

 are observable in patches o,f white calca- 

 reous matter on every sea-weed and shell, 

 appearing like delicate lace, and when 

 taken fresh from the water present the 

 appearance of fine net- work. 



FLUTE. 1. A musical wind instrument, 

 consisting of a tube about eighteen inches 

 in length, furnished with lateral holes at 

 the side, for the purpose of fingering. 

 This is the English flute ; but the German 

 flute is formed of several joints or pieces 

 crewed into each other, with holes, and 

 several keys, to modify the tones to the 

 various sharps and flats. In this sense 

 the term is from flo, flatus, to blow. 2. 



Cfi 



In architecture, see FLUTINGS. 3. In na- 

 vigation, a small vessel or boat wiin faat 

 ribs, to carry provisions for fleets or eq.ua- 

 drons. In this sense the term is a different 

 orthography of '.float orflota, Gena.flite. 



FLUTED, grooved, channelled, furrowed. 



FLU'TINQS, ) In architecture, longitu- 



FLUTES. } dinal cavities or channels 

 cut in the shaft of a column or pilaster. 

 Fluting is employed chiefly in the Ionic 

 order, sometimes in the Composite and 

 Corinthian, rarely in the Doric and Tus- 

 can. Fluted columns are sometimes 

 termed reeded. 



FLUX, Lat. jtftM-u*, a flowing. Any flow 

 or issue of matter. In nosology, a general 

 name for diarrhoea, dysentery, and cho- 

 lera. In chemistry, a name for any admix- 

 ture to promote the fusion of earths or 

 metallic ores by heat. While flux is the 

 residuum of the deflagration of two parts 

 nitre, and one part cream of tartar : it is 

 a carbonate of potash. Black flux is ob- 

 tained by deflagrating equal parts of nitre 

 and tartar. 



FLux'ioN,Lat.^ua:to, a flowing. A term 

 used by the old chemists synonymously 

 with fusion. In mathematics, the term 

 fluxion denotes ihefluents,or flowing quan- 

 tities, increase or decrease ; and fluxions 

 denotes that branch of analysis wherein 

 magnitudes of every kind are supposed to 

 be generated by motion ; a line by the mo- 

 tion of a point, a surface by the motion of a 

 line, and a solid by the motion of a surface. 

 The increments are also sometimes called 

 fluxions, but more commonly fluents. 



FLY or FLIT-WHEEL. In mechanics, a 

 heavy wheel employed for equalising the 

 motion and increasing the effect of ma- 

 chines, revolving upon an axle, after the 

 same principle as a counterbalancing 

 weight. The general object is to conduct 

 the motion over the dead points, or those 

 parts where the crank has least effect, as 

 in stationary steam engines. The fly of 

 the mariner's compass is that part on which 

 the 32 points are described. 



FLY-BOAT. 1. A large flat-bottomed 

 Dutch-built vessel: burden from 400 to 

 600 tons: named also flight. - 2. Along 

 narrow boat used on canals, called other- 

 wise a swift-boat. 



FLY'ERS. In architecture, stairs that do 

 not wind, but go straight forward, the 

 steps being all parallel. 



FLY'INO-BUTTRESS. In Gothic architec- 

 ture, a buttress built as an arch, springing 

 from a solid mass of masonry, and abut- 

 ting against the springing of another 

 arch. Its office is to act as a counterpoise 

 against the vaulting of the nave. 



which is able by the vibration of its large 

 pectoral fins to rise above the water when 

 pursued, and to maintain itself in the air 

 for a few seconds. 



