N ANJJ TIIK JI YI>K< K'AKIK >NS 341 



sition could take place. Diamonds have several times been success- 

 fully produced in the shape of minute microscopic crystals having the 

 appearance of a black powder, but when viewed under the microscope 

 they appeared transparent, and possessed that hardness which is the 

 peculiar characteristic of the diamond. This diamond powder is de- 

 posited on the negative electrode, when a weak galvanic current is 

 passed through liquid chloride of carbon. 17 



Judging from the fact that carbon forms a number of gaseous (car- 

 bonic oxide, carbonic anhydride, methane, ethylene, acetylene, tfec.) and 

 volatile (such are, for instance, many hydrocarbons and their most simple 

 derivatives) substances, and also because the atomic weight of carbon, 

 C=12, approaches that of nitrogen, N = 14, and that of oxygen, O = 16, 

 a iid the compounds CO (carbonic oxide) and N 2 C 2 (cyanogen) are gases, 

 it must be argued that if carbon formed the molecule C 2 like N 2 and O 2 , 

 it would be a gas. And as through polymerism, or the mutual combina- 

 tion of molecules (as O 2 passes into O 3 or NO 2 into N 2 O 4 ) the tempera- 

 tures of ebullition and fusion rise (which is particularly clearly proved 

 with the hydrocarbons of the C n H 2 ,, series), it ought to be considered 

 that the molecules of charcoal, graphite, and the diamond are very com- 

 plex, seeing that they are not soluble, not volatile, and not fusible. 

 The aptitude which the atoms of carbon show for combining together 

 and forming complex molecules appears in all carbon compounds. 

 Among the volatile compounds of carbon many are well known, the 

 molecules of which contain C 5 . . : C- 10 . . . C 20 . . . C 30 , &c., in 

 general C,,, where n may be very large, and in none of the other ele- 

 ments is this faculty of complexity so developed as in carbon. 18 Up 



17 Hannay, in 1H80, obtained diamonds by heating a mixture of heavy liquid 

 hydrocarbons (paraffin oils) with magnesium in a thick iron tube. This investigation 

 was, however, not repeated. Diamonds are found in a particular dense rock, known by 

 tin- name of itacolumnite, and are dug out of the debris produced by the destruction 

 of the itacolumnite by water. When the debris is washed the diamonds remain behind ; 

 they are principally found in Brazil, in the provinces of Rio and Baliia, and at the Cape 

 of Good Hope. The debris gives the black or amorphous diamond, carbonado, and th^ 

 ordinary colourless or yellow translucent diamond. As the diamond possesses a very 

 marked cleavage, the first operation consists in splitting it, and then roughly and finely 

 polishing it with diamond powder. It is very remarkable that Professors P. A. Latchinoff 

 and Erofeeff found (1887) diamond powder in a meteoric stone which fell in the govern- 

 ment of Penza, in the district of Krasnoslobodsk, near the settlement of Novo Urei 

 (Sept. 1(. lSHr>i. Up to that time charcoal and graphite (a special variety, cliftonite) had 

 been found in meteorites and the diamond only conjectured to be therein. The Novo 

 Urei meteorite was composed of siliceous matter and metallic iron (with nickel), like 

 many other meteorites. 



18 The existence of a molecule S 6 is known, and it must be held that this accounts 

 for the formation of hydrogen persulphide H.,S 5 . Phosphorus appears in the molecule 

 P 4 and gives P 4 H._>. When expounding the data on specific heat we shall have occasion 

 to return to the question of the complexity of the carbon molecule. 



