204 HISTORY OF CHEMISTRY. 



nation of the results of chemical manipulation, and 

 which is proved to be complete as to quantity, by 

 the balance, since the whole can only be equal to 

 all its parts. It is impossible to maintain that new 

 substances may not hereafter be discovered; for 

 they may lurk, even in familiar substances, in doses 

 so minute that they have'not yet been missed amid 

 the inevitable slight inaccuracies of all analysis, in 

 the way in which iodine and bromine remained so 

 long undetected in sea- water; and new minerals, or 

 old ones not yet sufficiently examined, can hardly 

 fail to add something to our list. As to the possi- 

 bility of a further analysis of our supposed simple 

 bodies, we may venture to say that, in regard to 

 such supposed simple bodies as compose a numerous 

 and well-characterized class, no such step can be 

 made, except through some great change in che- 

 mical theory, which gives us a new view of all the 

 general relations which chemistry has yet disco- 

 vered. The proper evidence of the reality of any 

 supposed new analysis is, that it is more consistent 

 with the known analogies of chemistry, to suppose 

 the process analytical than synthetical. Thus, as 

 has already been said, chemists admit the existence 

 of fluorine, from the analogy of chlorine ; and Davy, 

 when it was found that ammonia formed an amal- 

 gam with mercury, was tempted to assign to it a 

 metallic basis. But then he again hesitates 5 , and 

 doubts whether the analogies of our knowledge are 



5 Elem. Chem. Phil. 1812, p. 481. 



