CHEMISTRY AND ITS DEVELOPMENT 219 



though respectively an acid and a base, contained no 

 oxygen. The structure of the entire theory became some- 

 what shaky when the correctness of Davy's views was 

 finally recognized by all, including Berzelius himself 

 (1820). Nevertheless, Berzelius, and with him the entire 

 chemical world, continued to adhere to the electro-chemical 

 theory, and thus a strictly dualistic conception of com- 

 pounds continued to reign in the science. The thirties, 

 however, brought much new evidence against Berzelius' 

 principles. First of all it was recognized that electrolysis 

 breaks up a salt, primarily not into two oxides, but into a 

 free metal and an acid radicle. For example, potassium 

 sulphate is broken up, primarily, not into K 2 and S0 3 , 

 but into 2K and the radicle S0 4 . This made it evident 

 that sulphuric acid was not S0 3 , but H 2 S0 4 (i.e. S0 3 chem- 

 ically combined with H 2 0), because the S0 4 radicle was 

 seen to be the true acidic component of potassium sulphate. 

 Two important conclusions thus thrust themselves upon 

 chemists: (1) An acid is not a binary compound of oxygen 

 with an electro-negative element, but a combination of 

 hydrogen with an electro-negative radicle; (2) a salt is not 

 a compound of two oxides (e.g. K 2 O.S0 3 ) but a combination 

 of a metallic element with the electro-negative radicle 

 (e.g. S0 4 ) of an acid. The first of these conclusions, to- 

 gether with Davy's discovery that hydrochloric acid con- 

 tained hydrogen but no oxygen, indicated that not oxygen, 

 but hydrogen, is an indispensable component of acids, and 

 this vie:v was further strengthened by Graham's and 

 Liebig's classical studies of the so-called polybasic acids. 

 But so profound was Berzelius' belief in dualism, and so 

 great was his authority, that the electro-chemical theory 

 still continued to stand, and the conclusions just pointed 

 out were not generally accepted for some years. The final 

 blow to dualism came from the young organic chemistry, 

 in which the electric theory had been applied as generally 

 as in the inorganic branch of the science. About the middle 

 of the thirties Laurent and Dumas made a series of im- 



