1903.] MABERY—THE COMPOSITION OF PETROLEUM, 51 
Moissan’s work with the electric furnace, demands too many hypo- 
thetical assumptions, and it has too little support on the basis of 
fact. ‘To reason from the artificial formation of alloys and carbides 
in an electric furnace to the natural formation of petroleum con- 
taining nitrogen, sulphur and oxygen, in the form of hydro- 
thophenes, hydrochinolines, and phenols, demands a too broad 
reach of the imagination to make the connections. 
Bearing in mind the fact that petroleum may now be regarded 
as one and the same substance whatever its source, and that the 
deposits in different fields are composed of the same series, differing 
only in the proportions of these constituents, it must be admitted 
that it had one origin and one only. With reference to the 
series of hydrocarbons, it is immaterial whether its source was ani- 
mal or vegetable, for under the influence of natural agencies it 
could have been formed as well from one as from the other. 
This question has been attacked on chemical grounds from the 
wrong direction. Because hydrocarbons of the marsh gas series, 
ethylene series or acetylene series at temperatures of decomposition 
form minute quantities of the aromatic series, or that hexahydro- 
aromatic bodies are formed from the aromatic hydrocarbons by 
heating with hydriodic acid, to assume that these same changes 
were produced by natural agencies and resulted in the formation of 
the hydrocarbons which now constitute petroleum, together with 
the other constituents of petroleum, ascribes to these natural 
agencies a direction of action and power that we do not know they 
possess. 
In considering present knowledge with reference to the natural 
formation of petroleum, it seems to me that the following questions 
must be answered : 
1. What is the chronology of petroleum: in what order were 
the deposits formed in different fields ? 
2. Were the least volatile constituents formed from the most 
volatile or the reverse ? 
3. What is a reasonable explanation of the formation of the other 
constituents of petroleum ? 
The first question must be answered by the geologist. 
It is natural to assume that the limestones formed by the accumu- 
lation of the shell remains of animal life were deposited first from 
the ancient sea. The sandstones, as products of erosion from the 
older rocks, were deposited last. The question as to whether the 
