( 95 ) 



Ni SO^ 7 aq. or Ni SO, (> ji(|. « we ohlaiii aflei- some liiiu' ci'vstals 

 of Ni SO, 3 H._j 0.3 CH,0. Ir is liowevci- nol iinpossihle tiiat, afler 

 dissolving, the hydrate loses water with a certain rapidit}^ and coin- 

 bines with the niethylalcohol so that a definite stationary condition 

 is not alhiined immediately. If such were the case we might expect 

 that this modification in the condition of the solution would become 

 evident, say, by a change in the conductive power. 



In carrying out the experiments the conductive power was first 

 determined as quickly as i)ossible after preparing the solution (after 

 about 7 minutes). A portion of the solution (which contained about 

 57,1 of llie >^'^ll) ^^'^s set aside at the ordinary temperature or l)oiled 

 for 15 minutes. In the latter case the solution was made up again 

 to its original weight. In no cases was a change of the conductivity 

 observed. The same applies to the methylalcoholic solutions of the 

 sulphates of copper and magnesium. The latter exhibits the peculi- 

 arity of becoming turbid on heating to 60° and of clearing again 

 on cooling; it Avas again proved that after heating at 60^ for 7 

 minutes and subsequent cooling the conductive power remained 

 unchanged. 



From these experiments we may therefore draw the conclnsion 

 that a stationarj' condition has very probably set in immediately 

 after the sulphates have dissohed in the inethylalcohol and that 

 the crystallisation of loAver hydrates or of alcoholhydrates, \\hich 

 sometimes occurs after a long time, must be looketl u|k)ii as a 

 phenomenon of retardation. 



2. Secondly, the conductive power was determined of NiSO, 7 atp, 

 NiSO, 6 aq., NiSO, 3 aq, 3 Cli^O and NiSO, 1 aq. dissolved in absolute 

 inethylalcohol and at decreasing concentrations. As observed, these 

 determinations were made with the ol)ject of studying the extent of 

 the electrolj^tic dissociation of nickelsulphate in inethylalcohol (in 

 connection with the contents of the preceding article). Previous re- 

 searches, particularly those of Carrara, had led to the result that, at 

 least with salts coin})Osed of univalent ions, the electrolytic dissociation 

 is very considerable, in many cases about 'Vs h) ^1 ^ of that in aqueous 

 solution. In the case of salts ^vith a bivalent ion the conductive 

 power in methjdalcohol is considerably smaller ^) ; that of salts 

 composed of two bivalent atoms has, as far as we are awai-e, not 

 yet been investigated in methylalcohol solution. 



The experiments were made at 18" according to the usual method 

 of KoHLRAUSCH — OsTWALD; the luetliy lalcoliol (sp. gr. 0.7397 at 18°) 



1) GoFFETTi, Gazz. Ghim. 33, 5G. 



7 



Proceedings Royal Acad. xViiiblerdam. Vol. VI. 



