48 S. Ff. Peckham—Pitch Lake of Trinidad. 
and bursts, thus forcing the center up and causing a slow but 
irresistible movement from the center towards the circumfer- 
ence, where the pitch continually rolls under, exactly as Man- 
ross has described it. His suggestions concerning the ebullition 
of the mass within the lake were confirmed to the very letter. 
This action is explainable in this wise: Mr. Richardson’s 
analysis of asphalt water shows it to be very rich in sul- 
phates. As has been elsewhere shown, sulphates, especially those 
of the alkalies, when in solution are decomposed, when the 
water containing them flows through strata impregnated with 
organic matter, into hydrogen sulphide and a carbonate of the 
oxide present. When hydrogen sulphide infiltrates strata con- 
taining carbonate of lime, gypsum is formed and sulphur 
deposited, or converted into free sulphurie acid.* 
The Miocene bituminous strata of Southern California are 
full of sulphur springs and numberless deposits of sulphur. 
One such deposit in the southern part of Kern County is sup- 
posed to contain several thousand tons of sulphur. 
The reaction between sulphates present in the lake water 
and the bitumen or other organic material of the formation, 
furnishes a ready explanation of the presence of hydrogen sul- 
phide; but I must confess that the odor of that gas was much 
less apparent about the lake than I had been led to expect. 
Analysis will alone show what the gases are that inflate the 
asphalt, but of their presence in enormous volume, there can 
be no question. Atarough estimate, I should say that from 
one-third to one-half the volume of the mass as it exists in the 
center of the lake, is gas. I also hazard the opinion that this 
gas makes the mass specifically lighter than water, else the 
tables described by Manross and Kingsley would not rise and 
spread on the surface of the water and further the masses of 
asphalt would coalesce, and the water would float upon the 
_asphalt. Moreover it is without any doubt, that through this 
motion or ebullition which is produced, not by escape of vapor 
generated by heat, but by gases forced upward by their own 
specific gravity through a yielding mass, that the asphalt and 
mineral matter which forms the floors and sides of the erater, 
are mixed together until the asphalt is saturated; i. e. it 
reaches such a condition of plasticity and viscosity, that it will 
no longer absorb any more mineral matter in presence of water. 
I cannot account for the almost uniform character of the mix- 
ture of water, bitumen and mineral matter, on any other 
hypothesis.+ 
* Proc. Am. Philos. Soc., x, 445. Bischoff, Chem. and Phys. Geol., (Cay. Soc. 
ue 28; Ibid., i, 15, 340. T. S. Hunt. Chem. and Geol. Essays, pp. 23, 87, 
+ Mr. Richardson asserts that 90 per cent of the 80 per cent of insoluble min- 
eral matter in the pitch is silica. As a possible explanation of the presence of 
