l!68 Oa the Identitij of Silex and Oxygen, 



hct the insignificance of zircon, glucinc, anJ indeed the 

 whole of the species of earths, none of which exists without 

 an association of silex — all comparison vanishes, there is 

 no estimate ; these are as the mere spots to the brightest of 



luminaries, and therefore, in all systematic classification, 

 should be separately arranged. 



Where then ought silex to be placed in the arrangement 

 of simple elements? — should it link with any other ponder- 

 able body as a species of the same genus, or preserve a 

 station to itself? Were I asked for an answer to such a 

 question, I would say — that seeing^ nothing to which it has 

 the slightest resemblance but oxygen-gas, of which I con- 

 ceive it to be the true base, here I would not only assign its 

 proper rank, but give it alao a precedence to all other elemen- 

 tary matters that had resisted decomposition. 



It is hardly necessary for me now to add, that I do not 

 consider o^-ygen in the state o'i gas to be a simple body ; for 

 whatever is susceptible of spontaneoiis change should al- 

 ways be deemed a compound of at least two elementary siib- 

 ^jtances. If one instance of this can be adduced, we may 

 naturally infer that others will be found; and, fortunately 

 for my present purpose, a most appropriate example has 

 lately occurred, which confirms this conclusion : I allude to 

 the experiments of Messrs. Allen and Pepys*, upon carbon 

 and carbonic acid, which appear to have been conducted 

 with unconniion precision and genius, Froni these gentle- 

 men we learn, that oxygen-gas is subject to spontaneous 

 change, pr, as they very properly express it, a deterioration; 

 /ind that this will happen, though the gas be of the purest 

 kind, that obtained from oxy-muriale of potash ; and even 

 when seciircd in glass vessels with glass-stoppers, 



paving assumed silex and the base of oxygen gas to be 

 synonymous and simple bodies, I shall now proceed, as far as 

 my humble pretensions and Jcnowledge of this subject wiU 

 permit, tqsubstantiate this position, by ofiering a few only of 

 the numberless lacts, which seem to confirm this identity. 

 It is a task, I confess, I have imposed upon myself; foi;', 

 ^laving nearly three years ago permitted my opinion to he 



*. Fljiioaopliical Transactions iS07. 



pub-! 



