INDEX. 



34-7 



Henry's law, 329 



Hering, on vapour densities, 178 



Hoffmann-Gay-Lussac method of deter- 

 mining vapour density, 176, 177 



Holborn and Valentiuer, radiation con- 

 stants, 250 



Hope, method of determining point of 

 maximum density of water, 37, 40 



Hopkins, on the influence of pressure on 

 the melting-point, 204 



Hydrochloric acid, molecular weight, 85 ; 

 specific heat, 85 ; molecular heat, 85 ; 

 radiations absorbed by, 235 



Hydrogen, thermometric use of, 10, 11, 

 300 ; melting and boiling points, 12 ; 

 expansion of, with rise of tempera- 

 ture, 42 ; co-efficient of pressure 

 increase when volume is kept con- 

 tant under rising temperature, 46 ; 

 atomic weight, 84 ; specific heat of, 

 84, 85, 86, 293, 294; atomic heat, 

 83, 86 ; heat conductivity of, 106, 

 107 ; as standard scale, 124 ; value 

 of 7 for, 139; effusion of, 141; 

 viscosity of, 146, 147 ; mean free 

 path of, 147, 149 ; collision fre- 

 quency, 147 ; number of molecules 

 in 1 cc. 149 ; diameter of molecules, 

 149; critical point of, 188, 199; 

 critical constants of, 191 ; liquefac- 

 tion of, 197, 199 ; critical pressure, 

 199 ; boiling and melting-points, 

 119; transparency of, to radiations, 

 235 ; radiation of, 243 ; intrinsic 

 energy of, 299 



Hydrogen thermometer, 49-50 



Hydrometer, U-tube, for measuring ex- 

 pansion of liquids by heat, 29-36 



Hygrometer, Kegnault's, 209-210 ; 

 Dines's, 210-211 ; wet and dry bulb, 

 211-212 ; chemical, 212-213 



Hygrometry, 209-215 



ICE, melting-point of, as zero of ther- 

 mometric scales, 4, 5, 12 ; use of, in 

 calorimetry, 72-73 ; specific gravity 

 of, 72 ; specific heat of, 83 ; mole- 

 cular heat of, 87 ; Davy's experi- 

 ment with, 111-112; action of heat 

 on, 157, 158 ; vapour pressure of, 

 173, 206, 309 et seq. ; melting of, 200, 

 206 ; freezing, 200 ; relative volumes 

 of water and, 201 ; regelation of, 

 201-203 ; effect of pressure on melt- 

 ing-point of, 203-207, 317-319; 

 isothermals of, 207 ; crystalline 

 forms of, 207 ; evaporation of, 208, 

 309-312 ; haloes and parhelia due 

 to crystals of, 216-217 ; preservation 

 of, 233 ; formation of, 233, 234 

 Iceland spar, heat conductivity of, 101 

 Ice-water change of state, 307-312 

 Indian ink, emissive power of, 226, 227, 

 231 ; absorptive power of, 229, 231 



Indiarubber, strain energy of, 112; in- 

 dicator diagram for stress and 

 strain in, 304 



Indicator-diagram for water-steam, 185- 

 188 ; of work done by a body in 

 expansion, 259-260; for stresses and 

 strains, 302-305 



Ingenhousz, on diffusibility of heat, 

 94 



Iodine, atomic weight, 86 ; specific heat, 

 86 ; atomic heat, 86 



Iron, linear expansion of, as rails, 

 bridges, pipes, &c., 17, 22, 25, 26; 

 Kamsden's method of measuring 

 expansion of cast-iron bars, 18, 19; 

 method of Bureau International des 

 Poids et Mesures, 19, 20; expansion 

 and contraction of, by heat and cold 

 used for drawing walls together and 

 fixing hoops, 25 ; specific heat of, 65, 

 81, 87 ; atomic weight, 87 ; atomic 

 heat, 87 ; heat conductivity of, 89, 

 92, 97, 98, 99, 100; electric con- 

 ductivity of, 100; velocity of light 

 in, 100 ; emissive power of, 226 ; 

 radiating power of, 239 ; value of 

 7 for, 270; indicator diagram for 

 stresses and strains in, 302-304 



Isentropics, 261 



Isometrics, 261 



Isopiestics, 261 



Isothermals, 186 et seq., 260 



Isotonic solutions, 328 



JAMIN, on vapour densities, 176; on 

 light and its heat effect, 224 



Jamin and Amaury, on specific heat of 

 water, 77 



Jamin and Richard, on specific heats, 

 294 



Jolly, air thermometer devised by, 48-49 



Joly, steam calorimeter of, 73-75 ; dif- 

 ferential steam calorimeter of, 75- 

 76 ; on specific heat of water, 78 ; 

 of air and other gases, 86, 294 ; on 

 the mechanical equivalent of heat, 

 119 



Joule, on specific heat of water, 76 ; 

 on the mechanical equivalent of 

 heat, 120-124, 127 ; on the velocity 

 of molecules, 140-142 ; on hydrogen, 

 199 ; on adiabatic changes, 287 ; on 

 energy taken up by an expanding 

 gas, 296 et seq. See also Thomson 



Joule and Playfair, method of ascertain- 

 ing temperature of maximum density 

 of water, 38-40 



KAMMERLINGH-ONNES, liquefaction of 

 gases, 198 



Kelvin (Lord), work scale of tempera- 

 ture, 9, 259 ; on heat conductivities 

 of substances, 103 ; on effect of 

 pressure on melting-point of ice, 203, 



