STATE GEOLOGIST. 309 
at the present time is somewhat related to the method by which Mendelejeff 
thinks the great repositories of petroleum have been produced. 
In the year mentioned in the last paragraph Cloez obtained hydrocar- 
bons resembling some of the petroleum products by the action of sulphuric 
acid on the carbides of iron and manganese. A year later (1878) he pro- 
duced a liquid resembling petroleum by the action of hot water on the car- 
bide of manganese. 
The studies of the French chemist Moissan have brought to light a 
large number of facts which seem to lend some support to the chemical 
theory of the origin of at least some of the petroleum and gas deposits. 
This chemist found that at very high temperatures most of the metals will 
combine with carbon to form substances called carbides. The most famil- 
iar one of these is calcium carbide, which is manufactured on the large scale 
for the production of acetylene. 
As 1s well known, acetylene is produced from calcium carbide by the 
action of water upon it. Some of the other carbides produce other hydro- 
carbons. Thus aluminum carbide produces pure methane when acted on 
by water. Others produce mixtures of hydrogen, methane, ethylene, etc., 
and a few yield in addition liquid hydrocarbons which closely resemble 
petroleum. Four kilograms of uranium carbide gave 100 cc. of liquid 
hydrocarbons with asphalt base. 
From these experiments Moissan concludes that if the interior of the 
earth were to, contain large amounts of carbides to which water were to 
find its way through cracks and fissures in the earth’s crust, gas and oil 
would result ; and the large amount of heat developed in the chemical reac- 
tion would produce a substance very similar to crude petroleum. That the 
interior of the earth may contain such carbides, is made to appear probable 
from considerations that would lead too far to discuss. | 
These theories may suit the chemist very well, but they fall short of 
meeting the demands of the geologist. In general it can be said that they 
have been developed without due regard for the geological conditions under 
which oil and gas are actually found. 
The theories given appear to require one element in common, namely 
great heat. Now this can be secured, so far as gas and oil are concerned, 
in only two ways,(1) by reaching great depths in the earth’s interior or (2) 
by intrusion of molten rock. The great oil fields of this country lie in the 
Mississippi basin, a region that has been singularly free from intrusions of 
molten material. These remarks apply equally well to the recently dis- 
covered pools along the Gulf of Mexico. It follows naturally from this 
that the great supplies of petroleum in the United States cannot have been 
produced through the agency of heat derived from intrusions of highly 
heated material. 
The other alternative, namely that the heat was obtained at great 
depths, is equally inadmissable. Not that high temperatures do not exist 
