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GLOSSARY. 



Hydrau'lic Depth. The depth which 

 a volume of flowing water would 

 take in a channel, whose breadth is 

 equal to the outline of the bottom 

 and sides of the actual bed. 



Hydrau'lic Head. The measure of a 

 given hydraulic pressure, expressed 

 in terms of the height of a baro- 

 metrical column of the fluid. 



Hydraulic Press. A machine in 

 which powerful pressure is produced 

 by water forced into a cylinder, and 

 therein acting on a piston which 

 raises a table on which the material 

 to be pressed is placed. 



Hydrau'lic Pressure. The pressure 

 which a liquid moving in a closed 

 channel, exerts on the surfaces by 

 which, it is confined. 



Hydraulics (Gr. u8o>p, hudor, water ; 

 auAo?, aulos, a pipe). The science 

 which teaches the application of the 

 knowledge of the forces influencing 

 the motion of fluids, to their con- 

 veyance through pipes and canals. 



Hydrenceph'alocele (Gr. v8up, hudor, 

 water ; ^yKe^aAoy, enJceph'alon, the 

 contents of the skull ; KTJATJ, Tcele, 

 a tumour). A hernial protrusion 

 from the head containing water. 



Hydrenceph/aloid (Gr. vSup, hudor, 

 water ; yitf<f)a\ov, enkeph'alon, 

 the brain ; et'Sos, eidos, from). Re- 

 sembling hydrocephalus or dropsy 

 of the brain. 



Hydri'odate (Hydrogen and Iodine). 

 A compound of h'ydriodic acid with 

 a base ; now described by chemists 

 as an iodide, or compound of iodine 

 with a metal, together with an 

 equivalent of water. 



Hydriod'ic (Hy'drogen and I'odine). 

 Consisting of hydrogen and iodine. 



Hydro- (Gr. vSwp, hudor, water). A 

 prefix implying the existence of 

 water; but, in chemical terms, 

 implying that hydrogen is a compo- 

 nent part of the substance. 



Hydrocarbon (Hy'drogen and Car- 

 bon). A compound of carbon and 

 hydrogen. 



Hydrocar'buret (Hy'drogen and Car- 

 bon}. A compound of carbon and 

 hydrogen. 



Hydroceph/alus (Gr. vSwp, hudor, 



water; Ke^aArj, keph'ale, the head). 

 A disease characterised by the 

 presence of water within the head ; 

 a dropsy of the membranes covering 

 the brain. 



Hydrochlorate(//v'c?ro#mand Chlor- 

 ine). A compound of hydrochloric 

 acid with a base : now described by 

 chemists as a compound of chlorine 

 with a metal, together with an 

 equivalent of water. 



Hydrochlo'ric (Hy'drogen and Chlor- 

 ine). Consisting of hydrogen and 

 chlorine. 



Hy'drocy'anate (Hy'drogen and Cyan' - 

 ogen). A compound of hydrocyanic 

 acid with a base : now described by 

 chemists as a compound of cyanogen 

 and a metal, together with au 

 equivalent of water. 



Hydrocyanic (Hy'drogen and Cyan - 

 ogen). Consisting of hydrogen and 

 cyanogen. 



Hydrodynamics (Gr. u8o>p, hudr>r, 

 water; Sui/a^tus, du'namis, force). 

 The science which treats of the 

 motion of liquids and the causes 

 influencing it. 



Hydro-elec'tric (Gr. u8p, hudor, 

 water ; electric). A term ap- 

 plied to a machine in which elec- 

 tricity is developed by the action of 

 the steam of water ; also to the 

 voltaic current into the combina- 

 tion of which a liquid element 

 enters. 



Hydroflu'ate (Hy'drogen and Flu'- 

 orine). A compound of hydrofluoric 

 acid with a base. 



Hydrofluoric (Hy'drogen and Flu'- 

 orine). Consisting of hydrogen and 

 fluorine. 



Hy'drogen (Gr. vSup, hudor, water; 

 ycvvaw, gennad, I produce). The 

 lightest of elementary bodies ; a 

 colourless combustible gas, which, 

 with oxygen, forms water. 



Hydrog'rapher (Gr. vSwp, hudor, 

 water ; ypcupca, grapho, I write). 

 A person who describes the physical 

 or geographical conformation of 

 seas or other bodies of water. 



Hydrog'raphy (Gr. vScop, hudor, 

 water; ypaQw, grapho, I write). 

 The science of describing the physi- 



