M. Hess on the Scientific Labours o/* Richter. 89 



C 42'14 ; according to Berzelius, Ca 56*29 + C 43-71. Not 

 only does Richter not choose the carbonate of alumina, but 

 he examines the question to discover why the carbonate of this 

 base treated by an acid disengages less carbonic acid than 

 another base. You see then the ambiguity that there is in 

 this substance by no means escapes him, and he continually 

 returns to it as an enigma. Richter, armed with so powerful 

 a principle as that which he had discovered, could not limit 

 the application of it to his own labours ; he also applies it to 

 those of others, and rectifies or confirms them ; for he was, so 

 to say, endowed with a sense more than his contemporaries. 



Berthollet had found, as Lavoisier says in his treatise on 

 chemistry, that 69 parts of sulphur absorb 31 parts of oxygen 

 to become transformed into sulphuric acid. Richter repeats 

 the experiment and comes to a very different result. He 

 oxidates sulphur by nitric acid ; then converts it into sulphate 

 of lime and obtains 947 parts of this latter for 222 of sul- 

 phur, which makes 856 parts for 201 of sulphur, whilst we 

 admit at present 857*1 . He then greatly approaches the truth, 

 but to deduce the composition of sulphuric acid, that of the 

 sulphate must be known exactly. This not being sufficiently 

 well known to him, he finds that 201 parts of sulphur absorb 

 227 instead of 300 of oxygen to be converted into sulphuric 

 acid (vol. v. p. 124), which compared to Berthollet's result, 

 is still a very beautiful approximation, since this latter had 

 only found 90 parts instead of 300. Then he is reproached 

 with Bergmann's researches on the sulphates of potash and 

 barytes. They are not just, he says, for if we suppose the 

 salts compound, as Bergmann points out, and if one of them 

 is mixed with a neutral salt, by which it may be mutually de- 

 composed, there will be an excess of acid or of base, which 

 cannot happen; everyone knows that the solutions remain 

 neutral (vol. vii. p. 94 and 95) : therefore his analyses are false. 



Klaproth had discovered strontian*; he describes and ana- 

 lyses several of its salts, without attention to Richter's prin- 

 ciples. The latter applies them and finds that the analyses 

 of Klaproth agree with the principle, and consequently that 

 they are exact. 



It is this very important discovery which has been attri- 

 buted to Wenzel. This question therefore demands an at- 

 tentive examination ; for, take this title from Richter, and vou 

 make him fall back into the category of ordinary philosophers. 



* [Strontian was first discovered by Dr. Hope; though its discovery about 

 the same time, or shortly after, by Klaproth, appears to have been an inde- 

 pendent one* — Edit.] 



