None
3io Transmission of f)ower, means of 64 Transvaal, ventilation requirements in 115 Trolley wires, danger from 3' ^ Tsude Adit (Japan), mention of 33 Tunnel, definition of 2 Tunnel cars, data concerning, table giving 169 figure showing 164-168 types of 164-170 Tunnel headings, direction of holes in 221 INDEX 449 PAGE Tunnel headings, number of holes in, table showing 219 Tunneling machines, features of 181 patents for, list of 188-201 requirements of 184 types of 185-187 use of, in English Channel tunnel 183 Turbine-wheels, as sources of power 55 efficiency of 57 features of 55 steam, efficiency of 58 features of 58 Turbo-compressors, advantages of 109 effectiveness of 92 features of 9i"93 figure showing 95 power required by 82 section through, figure showing 93 use of, for ventilation 112 U United States Reclamation Service, officials of, acknowledgments to 3 United States, early railway tunnels in 14 Unloaders for air compressors, use of 99 Utah Metals tunnel (Utah), air pressure used at 103 blast holes in, depth of 235 order of 220 car used at, features of 169 direction of air current in 1 14 drilling speed at 151 features of 48 grade of dynamite used in 241 power plant of, water supply for 66 pressure of ventilating current , 120 system of lighting 202 V V-cut, arrangement of holes in 226 Valveless air drills, merits of 156 Valve, butterfly, figure showing 134 merits of 156 tappet, advantages of 155 Ventilating current, air needed for 115, 1 16 arrangement of pipes for, figure showing 113 direction of, factors influencing 113 machinery for 1 1 1 pressure of 1 18, 119 size of pipe line for 121, 122 i 4SO INDEX FACE Ventilating machinery, selection of, factors determining 123 Ventilating pipe, capacity of, table showing. 120 Ventilation, of ancient tunnels 10 of tunnels, air required for 115, 1 16 Vertical column mounting for drills, merits of 214 Volumetric efficiency of air compressors 83 Wallkill Siphon tunnel (N. grade of dynamite used in 241 pyramid cut in, figure showing 224 Yonkers Siphon tunnel (N. Y.)» features of 38 Z Zinc chloride as timber preservative 271. 