[186] It has been shown that the formula of Ramsay and Young (p. 66) can be applied (with certain restrictions) to the interpolation and extrapolation of the solubility curve of a substance provided two (or three) points on the curve are known. In this case T, T_{1}, etc., refer to the temperatures at which the two substances--one the solubility curve of which is known, the other the solubility curve of which is to be calculated--have equal solubilities, instead of, as in the previous case, equal vapour pressures. (Findlay, _Proc. Roy. Soc._, 1902, 69. 471; _Zeitschr. physikal. Chem._, 1903, 42. 110.) [187] W. Müller and P. Kaufmann, _Zeitschr. physikal. Chem._ 1903, 42. 497. [188] W. O. Rabe, _Zeitschr. physikal. Chem._, 1901, 38. 175. [189] With regard to the limits of supersaturation and the spontaneous crystallization of the solute from supersaturated solutions, see Jaffé, _Zeitschr. physikal. Chem._, 1903, 43. 565, and the very interesting paper by Miers and Isaac, _Trans. Chem. Soc._, 1906, 89. 413. [190] _Annales chim. phys._, 1894 [7], 2. 524. [191] _Phil. Trans._, 1884, 175. 23. [192] Hissink, _Zeitschr. physikal. Chem._, 1900, 32. 543. [193] _Zeitschr. physikal. Chem._, 1903, 43. 313. [194] Guthrie, _Phil. Mag._, 1875, [4], 49. 1; 1884, [5], 17. 462. [195] See Roloff, _Zeitschr. physikal. Chem._, 1895, 17. 325; Guthrie, _loc. cit._ [196] Guthrie, _Phil. Mag._, _loc. cit._ Cf. Ostwald, _Lehrbuch_, II. 2. 843. [197] Guthrie, _Phil. Mag._, 1875 [4], 49. 269. [198] _Ber._, 1877, 20. 2223. [199] _Silz-Ber. Wien. Akad._, 1880, 81. II. 1058. [200] Guthrie, _Phil. Mag._, 1875 [4], 49. 206. [201] If in the neighbourhood of the cryohydric point solution should be accompanied by an evolution of heat, then as the solubility would in that case increase with fall of temperature, salt would pass into solution. [202] Walker, _Zeitschr. physikal. Chem._, 1890, 5. 193. [203] _Zeitschr. physikal. Chem._, 1897, 23. 418. [204] Provided the solid nitrile is not present in too great excess. [205] _Wied. Annalen_, 1886, 28. 328. Cf. Ostwald, _Lehrbuch_, II. 2. 872. [206] Walker, _Zeitschr. physikal. Chem._, 1890, 5. 193. Schreinemakers, _ibid._, 1897, 23. 417. Roozeboom, _Rec. trav. chim. Pays-Bays_, 1889, 8. 257. Bruner, _Zeitschr. physikal. Chem._, 1897, 23. 542. [207] Van't Hoff, _Lectures on Theoretical Chemistry_, I. p. 42. Ostwald, _Lehrbuch_, II. 2. 824. [208] Ostwald, _Principles of Inorganic Chemistry_, translated by A. Findlay, 2nd edit., p. 453 (Macmillan, 1904); Skirrow and Calvert, _Zeitschr. physikal. Chem._, 1901, 37. 217. [209] _Vide_ Loewel, _Annales chim. phys._, 1857 [3], 49. 32. Cf. Löwenherz, _Zeitschr. physikal. Chem._, 1895, 18. 82. [210] Loewel, _loc. cit._ Gay-Lussac, _Annales chim. phys._, 1819, 11. 296. For the solubility at higher temperatures, see Tilden and Shenstone, _Phil. Trans._, 1884, 175. 23. Étard, _Annales chim. phys._, 1894 [7], 2. 548.