Carbon^ Silicon^ and Nitrogen. 3 



chemistry supplies. It remains competent to whomsoever 

 chooses, to affirm, on the grounds of analogy, probability, direct 

 experiment, or whatever else may seem to warrant it, that 

 any or all of them are not simple substances : all that the 

 chemist contends for is, that, tested by their power to resist 

 the weapons and agents he can direct against them, they pre- 

 serve their simplicity. 



Professor Low would have the chemical elements included 

 among compound substances, because it violates the law of 

 continuity in nature, to suppose some 55 bodies simple, 

 whilst all the rest are compound. This may or may not be 

 true ; but it could do no service to term the elements com- 

 pound, unless we were prepared immediately to follow up the 

 statement, by shewing of what they are compounded. Such 

 a proposition is consistent enough on Mr Low's part, since he 

 offers a scheme of their composite constitution, founded on 

 certain hypothetical views ; but it is not competent to the 

 chemist. All the knowledge he possesses of the composition 

 of bodies, has been obtained by decomposing, or con^bining 

 them, or by transforming them without decomposition, into 

 each other. According to the characters they have shewn, 

 when thus treated, they have been named and classified in 

 the order of their complexity, and so as to shew, within cer- 

 tain limits, the nature and number of their several compo- 

 nents. But the elementary bodies being insusceptible of re- 

 solution into substances more simple than themselves, cannot 

 be affirmed to be compound in the sense the other bodies the 

 chemist considers, are ; and it is not his office to discuss their 

 complexity on other grounds than those afforded by their 

 behaviour, when subjected to analytic, synthetic, or purely 

 transformative forces. 



Whilst, therefore, I fully sympathise with the speculative 

 spirit that has led Mr Low to propose a scheme of elemental 

 constitution, and differ from most of my fellow chemists, in 

 believing that some such scheme will hereafter be realized in 

 our laboratories, I dissent from him in thinking that the 

 chemist has erred, in demanding that every undecomposed 

 body shall be considered simple. The term residual, or resi- 

 duary, might indeed be better than simple, as indicating more 



