46 
acknowledged. Liebig states, in his “ Chemistry in its 
Application to Agriculture and Physiology,” (3rd edition), 
that the quantity of carbon existing in the atmosphere 
amounts to more than the weight of all the plants and 
of all the strata of mineral and brown coal existing on 
the earth. This would seem to favour the notion that 
the mineral and brown coal available for combustion 
would not affect the atmosphere to any serious extent 
if consumed. He has assumed more carbonic gas to 
exist in the atmosphere (toVo by weight) than many 
authorities would allow. Moreover, since the book was 
written enormous deposits of fuel have been discovered. In 
another passage Baron Liebig seems to favour an opposite 
view, for he states — “ In former ages, therefore, the atmo- 
sphere must have contained less oxygen, but a much larger 
proportion of carbonic acid, than it does at the present time, 
a circumstance which accounts for the richness and luxuriance 
of the earlier vegetation.” Dumas and Boussingault say, in 
their book on the chemical and physiological balance of 
organic nature, “ If we suppose, then, that the whole of the 
carbon was diffused through the atmosphere in the shape of 
carbonic acid prior to the creation of organised beings we 
shall see that the atmosphere, instead of containing less than 
the one-thousand part of its bulk of carbonic acid as at 
present, must have contained a quantity which it is not easy 
to estimate, but which was perhaps in the proportion of 
3, 4, 5, 6, and even 8 per cent.” Mr. Hull, in his “ Coal 
Fields of Great Britain,” taking 4,000 feet as the depth 
capable of being worked, estimates the supply from the 
English and Welsh coal fields at 60,000,000 tons for 1,000 
years. In the same book it is stated that the American 
coal fields are 72 times greater than the English and Welsh. 
In the reports furnished to the Admiralty some years back, 
by Dr. L. Playfair and Sir H. De la Beche, there is given a 
table showing the average composition of Welsh, Newcastle, 
