HISTORY OF THE ATOMIC THEORY. 223 



a dose of sulphur invariably fixed by nature, and that it b 

 not in the power of man to increase or diminish it. He fixes 

 this at 25 per cent." 



Proust continues, " It is not I, but nature, or whatever 

 power you choose, which places a barrier between it and all 

 the efforts of every chemist who will attempt to make sul- 

 phuret of antimony above or below this proportion. / have 

 assigned no law to my discovery ; I have verified it only ; 1 

 have followed the precept which Berthollet himself has traced 

 in his profound work; when, says he, one substance combines 

 with another, it is necessary to determine the proportions, and 

 to examine the properties, &c. Such, in fact, has been the 

 constant object of chemists, from the moment that they recog- 

 nised that this determination was one of the most important 

 bases of the history of combinations and of the science of 

 analysis. Nobody can believe that nature will abandon her 

 compounds to the chance of those variable proportions which 

 Berthollet has chosen as the foundation of his system. But 

 it is not the less true, that in proportion as the horizon of 

 sulphurets extends, we do not see that the new facts which 

 every day accumulates are of a nature to strengthen it." 



Berthollet against Proust. " He has combined the oxide 

 of antimony with different proportions of sulphur, and has 

 obtained mixtures which may be represented by this formula; 

 oxide +1+24-3, &c., of the sulphuret of antimony: has he 

 not obtained there veritable combinations ?" Page 262. 



Proust: " To this, I shall reply, that solutions which have 

 commenced, or which have not attained the term of saturation 

 of which we consider them capable, ought to be viewed 

 differently from combinations which are completed; but to 

 explain myself, I illustrated those solutions in the same way I 

 would do those of sugar in water, that is, as water + 1 +2+3 of 

 sugar. I do not see that we can form more distinct ideas of the 

 solutions of the sulphuret of antimony in its oxide. All chemists 

 have hitherto believed that these glasses, livers, and crocuses, 



