APPENDIX. 511 



and friend, the late Dr. Samuel Brown, propounded his ingenious 

 Atomic Theory, and believed he had found an experimental sup- 

 port for his views in the conversion of carbon into silicon. This 

 alleged transmutation of elements created a great sensation in 

 the scientific world, especially as the then vacant chair of 

 chemistry at Edinburgh was claimed by his friends for Dr. Brown, 

 as an appropriate reward for his dissertations and discoveries. 

 But the reputed facts were denied ; and Dr. "Wilson undertook 

 to sift the matter to the bottom. He spent the winter of 1843-44 

 in repeating the experiments in conjunction with Mr. John 

 Crombie Brown, and they printed together an account of them j 1 

 and Dr. Wilson published a paper on isomeric transmutation, 2 

 in which the whole question was very calmly discussed, the 

 difficulty presented by the atomic weights fairly set forth, and the 

 statement made that the experiments were insufficient to prove 

 the important deduction which had been drawn from them. 



During the previous year, a discussion had arisen in the Zoolo- 

 gical Society of London, about the bones of that gigantic fossil 

 bird, the dinornis. Those bones, and those of many other extinct 

 creatures, were found to contain an enormous amount of fluoride 

 of calcium, instead of the doubtful trace which had been detected 

 in recent bones. The theory had been started by Dr. Falconer, 

 that this fluoride might have come from a transmutation of the 

 ordinary phosphate of lime, while the more orthodox opinion 

 was maintained by Mr. Middleton, that the fluoride had been 

 somehow dissolved and deposited in the bones while buried in 

 the earth. Here was just a question after Dr. Wilson's own 

 heart, especially as it glanced at the bewitching idea of trans- 

 mutation. He entered on the subject, and during several years 

 produced a series of papers, the titles of which are given below, 3 



1 ' Trans. E. S. E.,' vol. xv. part iv. 



2 'Edin. New Phil. Journal,' July 1844. 



3 On the Solubility of Fluoride of Calcium in Water, and its relation to the occur- 

 rence of Fluorine in Minerals, and in recent and fossil Plants and Animals. ' Trans. 

 R. S. E.,' vol. xvi. part ii. 



On the Presence of Fluorine in Blood and Milk, &c. ' Edin. New Phil. Journal,' 

 October 1850. 



On the Presence of Fluorine in Ocean Waters. ' Edin. New Phil. Journal,' April 

 1850. 



On Two New Processes for the Detection of Fluorine when accompanied by Silica, 



