1880.] On the Artificial Formation of the Diamond. 455 



stronger tubes were necessary for this reaction, or that some other 

 reaction would require to be found. 



I would here mention a fact which, although not directly connected 

 with our subject, is of great interest to students of chemical physics. 

 When introducing the alkali metal into the tube it was often necessary 

 to push it down with a rod, and in one or two cases when I had mis- 

 laid the iron rod for the purpose I used a glass rod, of which the end 

 had not been rounded by fusion. In consequence, some small particles 

 of glass became detached, and being lead glass they were heated to 

 such a temperature that they were softened, and in some cases com- 

 pletely melted by the heat. Whenever this had taken place the piece 

 of glass had cavities in it, and these cavities were partially filled with 

 liquid or compressed gas, generally with a portion of each. In the 

 same piece of glass the bubbles were of different size, and often filled 

 to different heights with liquid, just as we find liquid carbonic acid 

 and water filling in different proportions the cavities in the same quartz 

 crystal. How these cavities in the glass are formed, and how the 

 liquid gets into them, I cannot at present determine, but even little 

 spheres of glass purposely introduced likewise developed cavities con- 

 taining liquid on being fused under pressure. As this is a part of the 

 subject I am investigating, the results being easily produced, I shall 

 reserve its full discussion until I have examined it from various points 

 of view, and varying the substances employed. I think it right to 

 mention it here, however, as I have so little leisure and so many inte- 

 resting discoveries just touched upon, and each one more tempting as a 

 field of labour than the other, that it may be some time before I can 

 have full data on the subject. 



The iron used in making the tubes is what is known as " Lowmoor " 

 iron, a very pure and strong quality, and a portion removed from the 

 interior of a tube which has been used gave, on analysis, 217 per cent, 

 of carbon, showing to what an extent carbonisation had gone on. 



Having obtained results from this process of a kind which showed 

 that diamond was unlikely to be formed by its agency, I reverted to 

 the original idea of solution of carbon in a gaseous menstruum, and 

 from some experiments I had been carrying on with the view of finding 

 some commercial use f or " bone oil," I concluded that the distillate 

 from boue oil containing the nitrogenous bases would be most likely 

 to yield such a solvent. Bone oil, the nitrogenous distillate obtained 

 in the manufacture of bone char, and for a plentiful supply of which 



1 am indebted to Messrs. John Poynter and Sons, of Glasgow, was 

 distilled, and the portion boiling between 115° and 150° was taken and 

 rectified over solid caustic potash, and latterly over sodium. When 

 satisfied that it was free from moisture, oxygen, and sulphur, a tube. 



2 j" X 20" X y bore, was three parts filled, and some charcoal powder 

 added, and the whole welded up solid. I found that the nitrogenous 



2 k2 



