16 On Isomeric Transmutation^ and the Nature of 



professes not only to have decomposed nitrogen into silicon 

 and hydrogen, but to have combined silicon and hydrogen into 

 nitrogen ; so that he offers both synthetic and analytic proof 

 of the truth of his views. It is impossible, however, to judge 

 of the value of Mr Knox's experiments, till we see them re- 

 ported in full ; and there is a hesitation in his view of the 

 constitution of nitrogen, as to whether it contains oxygen or 

 not, which might, and should have been removed by prolonged 

 experiments, before he published on the question at all. 

 Moreover, he determines nothing as to the quantitative con- 

 stitution of nitrogen, which should surely have been the chief 

 object of investigation, as soon as he saw reason to believe 

 that nitrogen was not a simple body. 



As to the relative probability of the rival theories of the 

 origin of the silicon, which appeared when paracyanogen was 

 subjected to Dr Brown's processes, it is impossible at present 

 to give a decision. I have repeated none of Mr Knox's expe- 

 riments, and it would be presumptuous in me to criticise his 

 results ; but I devoted the greater part of last winter, along 

 with my friend Mr John Crombie Brown, to the repetition of 

 Dr S. Brown's processes for the transmutation of carbon into 

 silicon, and I am free to offer an opinion on their value. Those 

 who wish to know in detail the results my colleague and my- 

 self arrived at, will find them in the fifteenth volume of the 

 Transactions of the Royal Society of Edinburgh.* Our gene- 

 ral conclusions may be stated in a word. 



We were able to confirm Dr Brown's phenomenal results 

 thus far, that we obtained silicon in several of our experiments, 

 in circumstances which seemed, to myself at least, to preclude 

 the possibility of its being derived as an impurity or accidental 

 ingredient, from the vessels or materials, or reagents made use 

 of. The quantity was alv/ays much less, than by Dr Brown*'s 

 hypothesis it should have been, and much less than he him- 

 self procured ; in many experiments, moreover, no silicon was 

 obtained at all. So far, however, as this scanty and precarious 



Mr Knox's results in this way. His hypothesis aflfords no explanation 

 of the latter gentleman's synthetic experiments on the formation of ni- 

 trogen from silicon and hydrogen. 



* Pp. 547-559. 



