88 M. Hess on the Scientific Labours of Richter. 



performed analysis with skill enough, that Richter remained 

 all his life uncertain on several points. 



Here is certainly one of the most striking proofs of the pro- 

 gress we owe to him. He makes analyses, and deduces a general 

 principle from them, and from that time these same analyses 

 are no longer sufficient for the increasing wants of the science. 

 To set out from hence the task imposed by Richter becomes 

 gigantic. New methods are necessary. We owe them to M. 

 Berzelius ; it is he who executed this work with a precision 

 very rarely equalled, and which not only has not been sur- 

 passed, but never will be by these methods. 



Richter, after having established this principle, continues to 

 apply himself to the subject; he determines the capacity of 

 saturation of acetic acid, by lime, by magnesia, by barytes, 

 and finds that in order to saturate 1000 parts of this acid, sup- 

 posed anhydrous, Ca 523, Mg 405*6, Ba 1465 are necessary, 

 which gives for the composition of these salts, 



According to Richter. According to Berzelius. 



For 100 of Ca A . . Ca 34-34. A 65*66 Ca 35-63 A 64*37 

 MgA..Mg28*8 71'2 Mg28*66 71*34. 

 Ba A . . Ba 59* 4 40* 6 Ba 59* 8 40* 2 



Let us observe that there is no question of alumina ; it is, 

 says he, because he is not able to find with precision the point 

 of saturation for this base. You therefore see a real difficulty 

 which stops him, this combination being one of those which 

 he is more certain of determining by calculation than by ex- 

 periment. 



These researches lead Richter to the conclusion that acetic 

 acid follows the same law as the acids before considered. He 

 then shows that the same law is also applicable to the citric, 

 oxalic, tartaric, formic, and several other acids. It is essential 

 to observe, that in order thus to prove by experiment the ge- 

 nerality of the principle which he had established, an entire 

 series of analyses was necessary for each acid, and it will be 

 easy to judge of the ardour and time he must have expended 

 on these labours. But in these same works he applies his 

 principle ; as for example, he often meets with difficulties in 

 finding the point of saturation for carbonic acid, he sets out 

 then from a combination which he thinks well known. There 

 again he avoids alumina as not adapted to his object, and he 

 selects carbonate of lime. His choice could not then fall better. 

 He finds that 1000 parts of carbonic acid are saturated by 



1373 parts of lime, which gives for 100 parts Ca 57*86 and 



