LECTURE VI.] HISTORY OF CHEMISTRY. 89 



when subjected to the influence of the electric current), that he 

 only regarded one particular view as possible. 



As an appendix to the compounds, Berzelius takes solu- 

 tions into consideration. He does not place these in the same 

 class with the compounds, because a disappearance of heat is 

 observed during their formation, and therefore no electrical 

 discharge can take place in the operation. 8 



Before proceeding to the further statement of the system 

 of Berzelius (especially before turning to his interesting and 

 extremely important method of atomic weight determinations) 

 I wish to say something about the nomenclature 9 and the 

 system of notation, 10 which he had proposed some years 

 before. In doing so, I can be all the more concise, as the 

 former is merely the perfecting of the system introduced by 

 Guyton, Lavoisier, Berthollet, and Fourcroy, 11 and both are, 

 no doubt, well known. I can, therefore, confine myself to 

 what is of essential importance, or is characteristic of the point 

 of view of Berzelius. 



Substances are divided into ponderables and imponderables. 

 Amongst the latter we find electricity, magnetism, heat, and 

 light. The former are divided into elements and compounds, 

 solutions and mixtures. Amongst the simple substances, 

 Berzelius places the metals and the metalloids. He uses a 

 word here which Erman had employed before him for desig- 

 nating the metals of the alkalies and of the earths; 12 but 

 Berzelius is the first to give it the meaning that we still attach 

 to it. 



The oxygen compounds are either called oxides or acids. 

 The substances of this class which possess neither basic nor 

 acid properties, and contain relatively little of the negative 

 element, are called sub-oxides. The basic salt-forming oxygen 

 compounds are designated oxides ; when an element or a 

 radical forms two substances of this kind, these are distinguished 

 by the terminations of the specific name. This is very easy 



8 Lehrbuch. 3, part I, 80. 9 Journ. de Phys. 73, 253. 10 Essai etc. 

 ill. u Compare p. 32. 12 Gilb. Ann. 42, 45. 



