474. Our Coal Supply and our Prosperity. [ Oct., 
“an ounce of the wire is therefore equal in light-giving power to 
33 lbs. of sperm candles.” The Drummond light (oxyhydrogen) we 
will pass over; its power varies from 19 to 153 candles, according 
to the gas in which it is burned—coal-gas being the lowest ; and as 
to the power of the electric light, it “varies from 650 candles to 
1,444, the average being about 1,000!” 
This is Dr. Letheby’s opinion; but according to the view of 
Mr. Crookes (who, in his article on the subject, enters more fully 
into details), the hghting power is immeasurably greater ; and when 
he first entered into a calculation of the cost of working Mr. Wilde’s 
machine, he estimated roughly that it would require 114 lbs. of coal 
to produce with it a ight of 4,000 candles for one hour! 
The whole inquiry is still an open one, and is practically in its 
infancy. If we were asked to decide whether or not we should 
continue during the next ten or twenty years to employ coal as the 
direct source of our light, we should certainly answer affirmatively ; 
but taking vested interests, gas-pipes, fittings, and all that sort of 
thing into consideration, we should not be disposed to give coal-gas 
a lease of more than twenty or thirty years. In fact, with our 
present information and experience, we may pronounce it the very 
height of absurdity to assert that, a few more years having passed 
over our heads, the employment of coal-gas for illuminating pur- 
poses may not begin to wane, and it would be equally foolish to 
deny that it may entirely cease to be used within the next fifty 
or one hundred years. 
We cannot, however, close our eyes to the fact that an enhance- 
ment in the price of coal, to which we are lable at any time, even 
from the cry of coal exhaustion, might cause us serious temporary 
inconvenience, and this more particularly in the matter of ballasting 
our vessels. But even here the facts have been misconstrued, and 
the matter has been considered in only one of its aspects. 
At present we have not only an export of about 9,000,000 
tons, which gives employment to our shipping, and serves abroad 
as current coin in payment of imports, but a large quantity of 
coal is taken out by our steamers to be burned on the passage 
home. Should the price of coal rise at home, it would, as matters 
stand at present, rise also abroad, and would stimulate the pro- 
duction of coal out of England; thereby not only injuring our 
barter trade, but compelling us to have recourse to other substances 
of a less “ paying” kind for ballast. 
This is the unfavourable view of the question; but it has also 
a favourable aspect, and this we can best exhibit by following 
Mr. Jevons in another of his erroneous arguments. ‘ 
More than once he draws attention to the fact* that sailing 
ships are gradually disappearing from the ocean, and that steamers 
* «The Coal Question,’ pp. 98 and 250. 
