20 On Isomeric Transmutation^ §fc. 



professed to establish his doctrine, than against the doctrine 

 itself ; and so far as this implied a resolution to accept nothing 

 but the most rigidly quantitative experiments, in proof of so 

 revolutionary a proposition as that of transmutation, it was 

 quite justifiable. The instrument par excellence of chemistry 

 is the Balance ; and every chemist must expect to have his 

 discoveries literally and metaphorically weighed in it, and re- 

 jected if found wanting. The Familiar Letters of Liebig, 

 e.g.f show that, although he unhesitatingly and too summarily 

 condemns Dr Brown's experiments, he willingly speculates on 

 the light which Isomerism may throw on the true constitu- 

 tion of the elements. 



And if chemistry is in favour of the doctrine we are con- 

 sidering, the other physical sciences justify it also. The 

 geologist acknowledges the existence of many phenomena, 

 in the relative distribution of the materials forming the earth's 

 crust, which seem inexplicable by our present chemistry. 

 The naturalist affirms that the whole subject of fossil zoology 

 is plunged in mystery; and anxiously demands if the ap- 

 pearance of substances in fossils, which no one can trace 

 to ordinary sources, does not depend upon a transmutation 

 of some of the pre-existing ingredients of these bodies.* 

 The agriculturist is frequently perplexed, in his endeavours 

 to trace the constituents of the plants he cultivates to the 

 soil they have grown upon. The difficulty is generally got 

 over by the accusation of imperfect analysis ; but some have 

 courage enough to refuse this argumentum ad ignaviam aut 

 ignorantiam, and one, Mr Rigg, who has been studying 

 the subject for years, declares that his observations have 

 led him to the conclusion, " that of the elements, carbon, 

 hydrogen, oxygen, nitrogen, sodium, potassium, calcium, fee, 

 which constitute the organic and inorganic parts of plants, 

 hydrogen is the only ultimate element, the rest being all com- 



* I refer particularly to a discussion which took place last winter in 

 the Zoological Society of London, as to the source of the fluoride of 

 calcium which appears in fossil bones. Literary Gazette, 2d December 

 1843, p. 773. The subject was afterwards referred to by Mr E. Solly, 

 in a lecture at the Royal Institution. 



