( 94 ) 



Fi-oiii l)utli cxperiiiieiils tlie coiK-lusion may bc di-awii tlial llie 

 liydiales of jiiL'kelsiilpliate wlicii dissolved iii iiiclliylalcohol only 

 retain one mol. of water of crystallisatifm. An experiment made with 

 KiSO^ 3 HjO 3 CH,0 gave as result .v — ± 2 and thus confirmed 

 the above conclusion. 



6. If now in a one per cent solution of the hydrates of nickel- 

 sulphate in metliylalcohol the salt still retains one mol. of water 

 notwitlistajiding the extreme dilution, it may in our opinion he taken 

 for granted that such is also the case in aqueous solutions. And 

 now })roceeding to concentrated an<i saturated solutions of hydrates 

 we arrive at the notion that the salt-nujlecule enters into a more 

 or less fixed combination with the water molecules and that, there- 

 fore, the hydrates (several simultaneously) are already present as 

 such to a certain extent iu the solutions from which they crystallise. 

 Probably thei'e exists in siu'h a system a highly complicated condition 

 of equililu'ium. 



Some years ago Pkkkking has proved by determinations of the 

 freezing |»oijits of solutions of sul]»huric acid (of dilfereiit concen- 

 trations) in glacial acetic acid that a delinite amount of \vater remains 

 in combination with the sulphuric acid. 



Amsterditin, June 1903. Onjan. Chcm. Lab. University. 



Chemistry. — ''The conductive po/rer of hj/dnftes ofnickelsulphate 

 dissolved in methylalcolwL" Uy Prof. C A. Lobky dk P>ruyn 

 and Mr. C. L. Jingius. 



The determination of the conductivity of hydiates of iiickelsulphate 

 dissolved in methylalcohol is important for two reasons. Fii'Stly, 

 in order to ascertain whether the condition of the dissolved substance 

 is modified after a shorter or longer period; secondly to ascertain 

 if possible (in connection with the preceding paper) to what extent 

 the salt is dissociated electrolytically. 



1. As regards the first point we recall the phenomenon that after 

 dissolving the sulphates (of Cu, Zn, Co, Mg, Ni) in absolute methyl- 

 alcohol the solutions (some rapidly, others slowly) deposit ^) lower 

 hvdrates or mixed alcoholhvd rates ; for instance from a solution of 



1) LoBRY DE Bruyn, Recueli, 11, 112 (1892) and Handelingen, 4e Natuur- en 

 Geneeskundig Congres, Groningen, 1893, p. 83. 



