1880.] 



On the Artificial Formation of the Diamond. 



451 



dissolved in water, some very hard scales of carbon are often obtained. 

 This was then the reaction on which my work was built. As potassium 

 is a metal of stronger affinities, I thought that an examination of its 

 action on paraffin would yield somewhat better results, but in this I 

 was disappointed. Sometimes its action was very great, but it seemed 

 to combine with some of the substance in the tube, and formed black 

 compounds, having no hard carbon amongst them. Some of the 

 experiments did yield a little, but on the whole it was not so good as 

 sodium. Lithium was next tried and yielded results which were much 

 more hopeful. When the same paraffin spirit was used the lithium 

 floated on it, bat by melting the metal in the bottom of the tube it 

 adhered to the sides, and did not float to the top unless any portion 

 became detached. The appearance shown by lithium is sometimes 

 very beautiful, a small globule of the metal when it has liquefied 

 showing, before it begins to act energetically upon the hydrocarbon, a 

 very beautiful play of colours. After this has gone on for a little a 

 more rapid reaction sets in as the temperature rises, and carbon is 

 deposited somewhat more plentifully. Sometimes a piece of the metal 

 will float until it becomes coated with carbon and it then sinks. The 

 carbon so obtained is harder than when sodium is employed, and will 

 often scratch glass easily. I thought that if I could by increased 

 temperature dissolve the nascent carbon in the metal I might obtain 

 diamond ; but after very many trials I did not succeed in doing so. 

 Many of my scientific friends who had witnessed my experiments 

 thought that a gaseous solvent for carbon might be found, and as this 

 was the direction of my general work, I abandoned these metallic 

 experiments and went into a more direct examination of the question 

 of gaseous solution. As by far the greater number of substances with 

 which we are acquainted are found by the intervention of water and 

 are only soluble in water, I thought that an examination of the solvent 

 effects of water under different circumstances would be likely to yield 

 important results. I found that hard glass tubes resisted the action of 

 water after it had passed its critical point for a time sufficiently long 

 to enable an observer to see whether any great change had taken place 

 in the solution contained in the tube. By these means it was found 

 that many chlorides, sulphates, and nitrates were as soluble in water- 

 gas as in water, if not more so, and that at least no sudden change of 

 solubility was observable at the critical point. By such a process, 

 however, only qualitative results could be obtained, and a series of 

 experiments was tried, using various volumes of water with a fixed 

 proportion of silica in iron tubes, and the solvent power of the water 

 estimated in a more accurate manner. An account of this work will, 

 I hope, be laid before the Society shortly ; in fact, as soon as I have 

 the necessary time for completing the work and writing it up. The 

 general result obtained from these experiments was that the solvent 



