=Hand-nut=, def., 23 =Hand pumps, classification of=, 187 points for erecting and operating, 204 =Hand rotary force pump=, ills. and des., 197 =Hand wheel for safety valve= of the underwriter pump, ills., 383 =“Hat” or flange hydraulic packing=, ills. and des., 154 “=Head of water=,” def., 23 =Heat units=, def., 23 =Hercules= (turbine) wheel, des. and ills., 132, 133 =Hero=, his first mention of steam, 200 years B. C., 279 =Hero’s water clock=, des. and ills., 39 “=Hesitates=,” def., 23 =High pressure steam=, def., 286 =High speed in pumps=, disadvantages of, 215 =Hill steam pump=, ills. and des., 305-306 =History of hydraulic engines=, 149 invention of the duplex steam pump, 335 =Holloway, J. F.=, historical quotation, 37 note relating to pumping oil, 341 =Hooker steam pump=, with outside valve gear, 301-303 =Horizontal jack=, ills. and des., 163, 164 pumps, why so called, 187 turbine wheel, des., 133 =Horse power apparatus=, combined pump, 201 theoretic, of Niagara Falls water wheels, 143 of a pump, def., 23 =Hose valves=, sizes for the underwriter pump, 383 “=Hump=,” def., 23 =Hydrant=, def., 23 =Hydraulic accumulator=, ills. and des., 171-173 =Hydraulic apparatus=, 154-184 pumps as, 181 =Hydraulic belt=, def., 23 pump, 200 =Hydraulic bolt extractor=, ills. and des., 164 data, 77-84 engine of Huelgoat, interesting note, 149 Ramsbottom’s, des. and ills., 148, 150-152 Brotherhood three-cylinder, 150-152 gauges, des. and ills., 115 =Hydraulic intensifier=, des., 173 =Hydraulic jack=, des. and ills., 158-162 =Hydraulic jacks=, pulling, horizontal, etc., 163, 164 relating to repairs and use, 161, 162 lifts and cranes, 180 machinery, broadly divided, 119 machine tools, 183, 184 motors, 147-153 motors, resemblance to high pressure steam engines, 149 =Hydraulic motor, the Compton=, 153 packings, 153, 154 pivot, def., 24 press, des. and ills., 169, 170 when invented, 53 punch, des. and ills., 165-167 =Hydraulic ram=, double, 177 table of capacity, 174 des. and ills., 180 =Hydraulics=, as a branch of engineering, 73, 74 as a term, how formed, 74 def., 73 =Hydraulics, elementary=, 71, 73-116 =Hydraulic shears=, def., 24 shock, def., 145 tourniquet, des. and ills., 126 valve, def., 24 wheel, def., 24 =Hydro-dynamics=, def., 73, 74 =Hydro-mechanics=, def., 74 as a branch of natural philosophy, 74 stress considered in a pressure, is always, 147 =Hydro-meters=, see note, 92 =Hydro-pneumatics=, 15, 75 =Hydrostatics=, def., 74 =Hydrostatic balance=, des. and ills., 93 paradox, data, ills., 78 =Impact=, def., 24 water wheels, 121 =India rubber= best for fire pump valves, 377 =Induction motors=, as used in mines, 275 special electrical quality of, 252