( 92 ) 



hydmtes are alreudy present as such in suliuioiis Irom Aviiieh they 

 crystallise and which are in eqnilibrinni with them. 



2. It might be expected that the study of solntions of hydrates 

 of sahs in a solvent other than water would contribute to the eluci- 

 dation of the i)roblem. In view of this, one of us ^) had already been 

 engaged some ten years ago with determinations of the elevation of 

 the boiling point caused l)y the introduction of hydrates of nickel- 

 sulphate into absolute methylalcohol. The preliminary conclusion 

 then arrived at, led to tiie assumption that a definite quantity of the 

 water (about 3 mols.) remained in combination with the NiSO^. 



In calculating the results of the experiments no notice was taken 

 of cei'tain fdctors, the importance of which was ulü<^no^vn or but 

 Httle appreciated in J892, namely the occurrence of electrolytic disso- 

 ciation, even in alcoholic solulloii and the intbicnce of a dissolved 

 volatile substance on the elevation of the boiling point. For tiiis reason 

 the former experiments were recalculated and partly extended. 



.3. In view of the last mentioned fact, we started with the detei'- 

 mination of the change in the boiling point caused by tiie introduction 

 of small (piantities of water into absolute methylalcohol. The fol- 

 lowing result was obtained (Barometer constant). 



EeelatioK of 

 CllfiU. IJ.,0. Ihilbij loint 



.^5.10 (Jrin. O..")720 Gnu. 0.291 

 0.353 

 0.416 



0.457 0.280 1 Averago 



0.528 0.275 ( 0.281 



O.Ü27 

 0.725 

 0.819 



These experiments, therefore, confirm the conclusion that water 

 added to methylalcohol causes an elevation of the boiling point from 

 the commencement and that no miiiimum boiling-point occurs 

 here as in the case of ethylalcohol and water (containing about 

 96 percent of alcohol) ^). 



^) LoBRY DE Bruym, Handelingen 4e Natuur- en Geneeskundig Congres, Gro- 

 ningen, 1893, p. 83. 



-) W. A. NoYEs and Warfel. J. Amer. Cli. Soc. 23. 463(1901). Sydney Young 

 and Emily Fortey, J. Ch. Soc. 81. 717 (190:2). The addition of 20 milligrs. of water to 

 50 grms of methylalcohol caused a perceptible elevaliun of the boiling-point. 



