226 The Americati Geologist. October, i89^ 
In 100 vols. 
Vols. Coj. Hg 
Granite, near Dublin, acid, Plutonic .... 5.0 9.4 90.6 
Granite, Ardshiel, acid, Plutonic 6.9 79.5 20.5 
Greisen, Altenburg, Sax., altered, Plutonic . 1.8 13.6 86.4 
Granulitc, India, altered, Plutonic .... 2.0 48.7 57.3 
, Quartz-Schist, Co. Down, Metomorphic . . 2.8 23.0 77.0 
Fuchsite Schist, Barodo, Inn., Metamorphic . 4.2 20.8 79.2 
21 Corundum rock, Rewah, Ind., Ind., Metamor- 
S phic 3.5 26.0 74.0 
Pyroxene Gneiss, Ceylon, Metamorphic ' . . 7.3 84.4 15.6 
I Gneiss with Corunbum, Seringapatan, Metamor- 
phic 17.8 18.0 82.0 
_; Gneiss with Game and Graphite, Ceylon . . 4.5 11. o 8g.o 
^ LGneiss, Himalayas 7.2 11.5 88.5 
3 5 Gneiss 5.3 82.3 13.6 
< ' Felspar 1.3 94-7 2.2 
■a 
S 13—79-2 13-522.9 
es 
® 5.4 40. 
These results give us an average of five and a half volumes 
of gas for every volume of rock, and of this quantity 40 per 
cent, was carbon-dioxide. Combining the averages we fin-d 
that these Archean minerals yielded between two and three 
times their vohmie of carbon-dioxide. Combining again with 
the previous result — 60,000,000 cubic miles of eroded crys- 
talline rock — we obtain about 150,000,000 cubic miles of gas. 
Of this the three-thousandth part will be carbon in the solid 
form. 
In this way the final result is reached; that by these 
minute contributions we get about 50,000 cubic miles of car- 
bon, equal to at least 60,000 cubic miles of coal. As the 
total stock of existing coal amounts to only about 2,000 cubic 
miles, or with all the other forms of unoxydised carbon, to 
not more than 50,000 cubic miles, we have a supply ample and 
more than ample for the demand. 
In such an investigation I need not caution anyone against 
laying much stress on the exact figures here given. A calcu- 
lation when the data are so indefinite can but be approximate. 
Yet I hope I have shown that allowing for all inaccuracy we 
have here a supply of the precious element, carbon, from 
which the geologist can obtain his coal without offending his 
brethren, the botanist and the geologist, by insisting upon a 
greater amount at any time in the atmosphere than they are 
