TRANSITION TO CLASSIFICATORY SCIENCE. 309 



was only discovered as late as 1826 ; and Fluorine, or Phtore, as, froir 

 its destructive nature, it has been proposed to term it, has not been 

 obtained as a separate substance, and is inferred to exist by analogy 

 only. The analogies of these bodies (Chlore, Phtore, &c.) are very 

 peculiar ; for instance, by combination with metals they form salts ; 

 by combination with' hydrogen they form very strong acids ; and all, 

 at the common temperature of the atmosphere, operate on other bodies 

 in the most energetic manner. Berzelius 3 proposes to call them halo- 

 fjenous bodies, or halogenes. 



5. The -number of Elementary Substances which are at present pre- 

 sented in our treatises of chemistry 4 is fifty-three, [or rather, as we have 

 said above, sixty-two.] It is naturally often asked what evidence we 

 have, that all these are elementary, and what evidence that they are 

 all the elementary bodies ; how we know that new elements may not 

 hereafter be discovered, or these supposed simple bodies resolved into 

 simpler still ? To these questions we can only answer, by referring to 

 the history of chemistry ; by pointing out what chemists have under- 

 stood by analysis, according to the preceding narrative. ^They have 

 considered, as the analysis of a substance, that elementary constitution 

 of it which gives the only intelligible explanation of the results of 

 chemical manipulation, and which is proved to be complete as to quan- 

 tity, by the balance, since the whole can only be equal to all its pails. 

 It is impossible to maintain that new substances may not hereafter be 

 discovered ; for they may lurk, even in familiar substances, in doses so 

 mjnute 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 somethino- to 

 our list. As to the possibility 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 chemical 

 theory, which gives us a new view of all the general relations which 

 chemistry has yet discovered. 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 synthe- 

 tical. Thus, as has already been said, chemists admit the existence of 

 fluorine, from the analogy of chlorine; and Davy, when it was foun.J 



3 Chem. L 262. 4 Turner, p. 971. 



