474 THE POPULAR SCIENCE MONTHLY. 



ON THE DISCOVEEY OF THE ELEMENTS. 1 



By WILLIAM ODLING, Esq., M. B., F. K. S., 



FULLERIAN PBOFESSOB OF OHE1USTBY AT THE EOYAL INSTITUTION. 



THE word " element " is used by chemists in a peculiar and very 

 limited sense. In calling certain bodies elements, there is no in- 

 tention on the part of chemists to assert the undecomposable nature or 

 essence of the bodies so called. There is not even an intention on 

 their part to assert that these bodies may not suffer decomposition in 

 certain of the processes to which they are occasionally subjected, but 

 only to assert that they have not hitherto been proved to suffer decom- 

 position ; or, in other words, to assert that their observed behavior, 

 under all the different modes of treatment to which they have been ex- 

 posed, is consistent with the hypothesis of their not having undergone 

 decomposition. 



The entire matter of the earth, then, so far as chemists are yet ac- 

 quainted with it, is composed of some 63 different sorts of matter 

 that are spoken of as elementary ; not because they are conceived to 

 be in their essence primitive or elementary, but because, neither in the 

 course of Nature nor in the processes of art, have they been observed 

 to suffer decomposition. No one of them has ever been observed to 

 suffer the loss of any substance different from the substance of its en- 

 tirety. Thus chemists are incapable of taking away from iron, for ex- 

 amjue, a something that is not iron; or of taking away from it any 

 thing whatever, so as to leave a residue that is not iron ; whereas they 

 are capable of taking away from iron-pyrites a something which is not 

 iron-pyrites but is sulphur, so as to leave a residue which is not iron- 

 pyrites but is metallic iron. 



The notion of all other material bodies being constituted of, and 

 decomposable into, a limited number of elementary bodies, which could 

 not themselves be proved to suffer decomposition or mutual transfor- 

 mation under any circumstances whatever, but could, on the contrary, 

 be traced respectively through entire series of combinations, and be 

 extracted at will from each member of the series, is a notion which, 

 undergoing in course of time a gradual development, was first put for- 

 ward in a definite form by Lavoisier ; until whose time, some residue 

 of the great alchemical doctrine of the essential transmutability of all 

 things that the substance of all things was the same, while the form 

 above was different still prevailed. To Lavoisier is due the enunci- 

 ation of the principle departed from, however, in a few instances by 

 himself that all bodies which cannot be proved to be compounded, 

 are in practical effect, if not in absolute fact, elementary, and are to be 

 dealt with accordingly. 



1 Lecture before the Royal Institution. 



