1879.] 



Researches in Chemical Equivalence. 



187 



whence n— '84093. The two sulphates, then, are equally precipitable 

 when the weight taken of each is '84093 grm. 



To calculate in what proportions the two sulphates must be mixed, 

 to give equal weights of precipitate, we have 



n_ (l + '21940 n) v 

 c 1-1845 7 



n = l — c 



If we put -=1, and combine these equations, the result is a quad- 

 7 



ratic, one of whose solutions is c = *5168, and consequently n= '4832. 

 Using these values in the primitive equations, the results are, 7= 

 '4363, i*=*4369, which we may regard as substantially equal. 



A highly important chemical relation is disclosed when the two 

 sulphates are so conditioned as to be equally precipitable. We have 

 seen that this is the case when n = c= '84093. Now the reciprocal 

 of '84093 is 1*1892, — a number differing by only the small amount of 

 0'40 per cent, from 1'1845, or 07. Deduced, as these values both 

 are, from a series of experiments, we cannot hold their connexion to 

 be accidental. It may be thus expressed in symbols, — 



07 c ' 



or we may state the relation thus : — For an equal weight, nickelous and 

 cobaltous sulphates are equally precipitable ; the attraction of the one 

 towards the reagent being then inverse to that of the other. 



In order to ascertain whether this function admits of extension 

 to other weights than '84093 grm. of the sulphates, we doubled all the 

 masses in one of our previous experiments (Y in the table), and 

 determined the chemical effect. The results were 



Uncorrected total precipitate 1*7840 grm. 1 



Containing of nickelous sulphate . . 0*8925 J 



0-8920 



The halves of these are 



0*4463 



5> 



Figures nearly identical with ? ???? " 1 



J 0*4465 „ J 



derived from Experiment Y. By doubling the mass, we thus produce 

 double the chemical effect. It is probable that this law is general ; 

 and, therefore, we infer that the reciprocal function we have noticed 

 may apply to multiples of the weights to which, in our particular case, 

 it specially appertained. Bearing in mind that MSO^CoSO^ 

 154*65, we accordingly write the function thus : 



0(NiSO i ) = (0CoSCg- 1 . 



