2 On Isomeric Transmutation, and the Nature of 



been spent in vain on these refractory substances. The 

 single and combined agencies of heat, light, electricity, mag- 

 netism, mechanical pressure, and the like, have been directed 

 in innumerable ways against them. But they have emerged 

 from every trial, except those we are soon to consider, with- 

 out betraying any sign of non-simplicity, or unfolding, if they 

 are compound, the hidden secret of their true nature. 



On the negative evidence of this insusceptibility of decom- 

 position, the residual undecomposed bodies have been termed 

 simple or elementary : they are the visible elements out of 

 which all things are made. It cannot be denied, however, 

 that in the minds of many, the term •' simpW^ has passed for 

 something more than the expression of " hitherto undecom- 

 posedy^ and has been accepted as fully equivalent to essentially 

 " indecomponihle?^ But it would be doing injustice to the 

 majority of chemists, to affirm that they have not employed 

 the word '■^ elementary^^ in its restricted and negative mean- 

 ing, and have been willing to acknowledge the possible com- 

 positeness of all the so-called simple bodies. I refer to this 

 the more particularly, that, in a curious volume recently pub- 

 lished by Professor Low, exception has been taken to the maxim 

 acknowledged among chemists, that a body should be con- 

 sidered simple till it can be shewn to be compound, and the 

 opposite opinion advocated, *' that a body is to be regarded as 

 compound, when we are not able to prove it to be simple."* 

 Mr Low is at great pains to shew, that the maxim he objects 

 to *' is unsound, and is arrived at, not * by the just logic of 

 Chemical Philosophy,' but by a chemical dogma which ought, 

 long ere now, to have been banished from the science into 

 which it has been introduced."! Every chemist, however, 

 will smile at this correction ; for the proposition that all bodies, 

 which cannot be resolved into something less complex than 

 themselves, shall be accepted as simple, is quite accurate, and 

 of much practical value, when taken in the sense in which he 

 uses it. The simplicity of the so-called elementary bodies, is 

 not affirmed to be intrinsic, essential, or absolute, but only to 

 exist in relation to the decomposing or modifying forces which 



* An Inquiry into the Nature of the Simple Bodies of Chemistry, by 

 David Low, F.R.S.E., &c. p. 9. 

 t Ibid. pp. 11, 12. 



