HAWORTH. | Origin of Oil and Gas. 189 
perimentation with various metallic carbides, some of which 
experiments have been repeated many times in other labora- 
tories. He found that different metals at high temperatures 
unite with carbon, forming a series of metallic carbides similar 
to the way iron in the smelting-furnace unites with carbon 
producing cast iron. The production of acetylene gas by the 
action of water on calcium carbide has just been mentioned. 
Aluminum carbide produces pure methane (CH:). Other me- 
tallic carbides produce various results, including free hydro- 
gen and quite a variation of hydrocarbons. Uranium carbide, 
it is stated, gave liquid hydrocarbons with an asphalt base. 
It seems that many different elements have the capacity of 
absorbing carbon under favorable circumstances and that the 
carbon thus absorbed may be obtained in one form or another 
by various processes. Even sticks of phosphorus, bought in 
the market for chemically pure, have been shown by Keiser 
and Remsen to contain traces of carbon absorbed during the 
manufacturing process. 
Recent discoveries bearing on the origin of the diamond also 
may be mentioned. In the Kimberly diamond-field diamonds 
are found in connection with a basic eruptive rock which has 
passed through a rich carbonaceous shale. When the im- 
portance of this condition was fully realized, about 1886, nat- 
urally it was supposed that the carbon came from the shale 
and was so explained by H. Carvill Lewis in his paper on the 
subject. Later Derby!** showed that the South-American 
diamonds occurred in an acid eruptive rock which probably 
had never come in contact with shale. More recent discove- 
ries have shown that diamonds occasionally are found embedded 
in acid eruptives far removed from shale walls, so that it is 
generally believed eruptive rocks of any description may con- 
tain at least traces of carbon. Even Kimberly diamonds are 
now found below the carbonaceous shale itself, leaving little 
ground for thinking the carbon came from the shales. 
The application, of course, is apparent, namely, that erup- 
tive rocks of almost any description contain traces of carbon 
held in some form, and that quite likely many of them contain 
comparatively large amounts of it. With present limitations 
on our knowledge regarding volcanoes, it is unsafe to state at 
what depths such lavas originated, and whether or not ground- 
waters could reach them, but it would seem reasonable to 
105. Lewis, H. Carvill: ‘Origin of the Diamond,” Science, vol. 8, p. 345. 1886. 
106. Derby, O. A.: Science, vol. 9, p. 57. 1887. 
