Behaviour of Chemical Compounds. 173 



number 11 '7. The magnetism of the dissolved chromic oxide 

 was therefore about 0*94 of that of the chromic oxide in the 

 salts, and nearly equal to that of the precipitated chromic hy- 

 drate : accordingly we cannot well assume that here the 

 chromic oxide is dissolved in the colloid state ; it is much 

 more probable that the chromium in the alkaline sohition is 

 approximately in the same state as in the peroxide-salts. 



If the chromic salts, e. g. chromic nitrate, be regarded as 

 consisting of Cr2 4- (N03)6, then in all salts in which chromium 

 in like manner enters into a combination with an electro- 

 neo^ative radical its atomic magnetism should be the same. 

 But if the solution of chromic oxide in potash were also to be 

 looked upon as the solution of a salt K2 + (04-Cr203), the 

 chromium would then be in quite another group of atoms 

 than that in which it was before, and it is fore-evident that 

 its magnetism must likewise be quite different ; its equality 

 in the alkaline solution of chromic oxide is perhaps a proof 

 that the chromic hydrate is dissolved as such unaltered in the 

 potash lye, and that it does not enter into a special electro- 

 negative group of atoms combined with the electropositive 

 metal potassium to form a saline compound. 



Precisely similar is the behaviour of the alkaline solutions 

 of the salts whose precipitation by potash &c. is prevented by 

 the addition of organic substances — for instance, solution of 

 cohaltous sulphate mixed with grape-sugar and potash. 



For example, the round glass, filled up to the mark with 

 19*6 grms. of solution of cobaltous sulphate, showed the mag- 

 netism 138, after deducting that of the glass and water. Then 

 only 8"1 grms. of the solution were poured into the glass, and 

 it was filled up to the mark with grape-sugar solution and 

 potash lye, when no precipitation took place. After deduct- 

 ing the diamagnetism of the solvent (the grape-sugar con- 

 taining potash lye), which differed but little from that of the 

 water, there remained the magnetism of the cobaltous com- 

 pound, equal to 57. 



While, therefore, the weights of cobalt employed in the 

 two cases were proportioned to one another as 19'6 : 8*1 

 ( = 100 : 41), the ratio of the magnetisms was as 138 : 57 (also 

 = 100:41). Here, then, the cobaltous hydrate is also pro- 

 bably dissolved unchanged ; a transition into the colloid state, 

 or the formation of special, differently grouped compounds 

 cannot with likelihood be assumed. 



[To be continued.] 



