68 HISTORY OF CHEMISTRY. [LECTURE V. 



and the connection between these two was now shown. The 

 further development of the electro-chemical theories appeared 

 at that time to be the highest aim of our science; at a later 

 date we see these theories abandoned. The extraordinary 

 enthusiasm was succeeded by an indifference just as extra- 

 ordinary. In those cases where it was formerly believed (as 

 regards the structure of the most complicated compounds) that 

 the real secrets of nature were being discovered, the ordinary 

 phenomena of decomposition were afterwards recognised. A 

 secondary importance only, was usually ascribed to the latter 

 in determining the constitution of substances. The electrical 

 properties of substances, which at that time also indicated their 

 position in the system, afterwards became of less consequence 

 in the determination of their chemical character. 



This is just such an example as is met with in the history 

 of every science. Some great end is achieved, in comparison 

 with which everything else becomes dwarfed into insignificance. 

 Every endeavour is turned towards development in the new 

 direction, and a system is established which has the observed 

 phenomena for its basis. Then facts appear which are in 

 conflict with the views- that have thus arisen. These facts are 

 a sufficient ground for some to abandon the theory ; but for 

 others they act merely as a stimulus to bring the new experi- 

 ments into harmony with the theory, and this compels them to 

 have recourse to further hypotheses. In this way a controversy 

 is developed which only ends when the supporters of the older 

 view have their eyes opened so as to recognise how greatly the 

 originally simple and elegant theory has been disfigured. The 

 whole system now falls to pieces, and it is no longer compre- 

 hensible how any one could have permitted himself to be guided 

 by such views. The greatest folly is now perceived in what 

 had been previously recognised as the highest wisdom. So the 

 times change ! 



The electro-chemical theories had the same fate. If we 

 consider the astonishing discoveries which were made by means 

 of the galvanic current, we can understand the importance 

 which attached at that time to electrical phenomena ; and I 



