T Tachydrite, influence of pressure on the transition point of, 263 Tartrate, dimethyl, 217 ----, sodium potassium, 259 Tautomeric substances, 195 Tensimeter, 91 Thallium nitrate and potassium nitrate, 192 Theorem of van't Hoff and Le Chatelier, 57 Thermometric determination of transition point, 337 Tin, 41 ----, lead, bismuth, 255 ---- plague, 43 ----, transition point of white and grey, 41 _p_-Toluidine and _o_-nitrophenol, 213 ---- and phenol, 214 Transformation of optically active substances, 220 ----, suspended, 37, 69, 89, 113, 137, 155 ----, velocity of, 70 Transition curve, 66 ---- ---- of Glauber's salt, 68, 140 ---- ---- of rhombic and monoclinic sulphur, 37 ---- interval, 270, 277, 315 ---- point, 34 ---- ---- for double salts, 258 ---- ----, influence of pressure on the, 68 ---- points, as fixed points in thermometry, 140 ---- ----, methods of determining, 331 ---- ---- of polymorphic substances, 63 Triangle, graphic representation by, 235 Triethylamine and water, 101 Triple point, 27, 55 ---- ----, arrangement of curves round, 56 ---- ----, changes at, 58 ---- ----, ice, water, vapour, 27 ---- ----, ice II., ice III., and water, 33 ---- ----, metastable, 38 ---- ----, monoclinic sulphur, liquid, vapour, 38 ---- ----, monoclinic and rhombic sulphur, liquid, 38 ---- ----, monoclinic and rhombic sulphur, vapour, 34 {350} ---- ----, red phosphorus, liquid, vapour, 47 ---- ----, rhombic sulphur, liquid, vapour, 38 ---- ---- solid, solid, vapour, 62 ---- ----, white phosphorus, liquid, vapour, 48 U Univariant systems, 16 V Van't Hoff, theorem of, 57 Vaporization curve, 63 ---- ----, interpolation and extrapolation of, 66 ---- ---- of water, 21, 23 Vapour pressure, constancy of, and formation of compounds, 90 ---- ----, dependence of, on solid phase, 88 ---- ----, influence of surface tension on, 2 ---- ---- in three-component systems, 261 ---- ----, measurement of, 91, 334 ---- ---- of calcium chloride solutions, 150 ---- ---- of ice, 25, 31 ---- ---- of small drops, 10 ---- ---- of sodium sulphate and water, 138 Vapour pressure of solid, solution, vapour, 126 ---- ---- of water, 21, 31 Variability of a system, 14, 16 Variance of a system, 16 Volatile components, two, 161