470 Our Coal Supply and our Prosperity. | Oct., 
per annum, will in 100 years be equal to 626,991,583 tons per 
annum, and 1,125,986,597 per annum in 112 years, and the coal 
to be used in making this iron, at the same rate for pig and wrought, 
would, according to this theory of geometric progression, be stated 
thus : —24,435,747 at 5 per cent. per: annum=39,213,331,617 per 
annum in 100 years, and 5,770,680,864 in 112 years. In 1961 
iron would use 2,775,796,665 tons of coal. But how does this 
correspond with the quantity Mr. Jevons has calculated upon? 
He states, from statistical calculations, that the total production of 
our coal-mines in England must im the year 1961 amount to 2,607 
millions of tons per annum to meet all the wants of England, 
including of course the manufacture of iron. So that we have here 
a very curious paradox reposing upon the incontrovertible logic of 
figures, viz. that the lesser quantity, although contained in it, still 
overtakes the greater, and we arrive at this ridiculous result, that 
the quantity of coal consumed for the making of iron alone exceeds 
the total quantity which Mr. Jevons lays down, according to the 
theory of geometrical progression, as required for the total con- 
sumption of the kingdom, including iron, 100 years hence.” 
We do not wish our readers to suppose that Mr. Jevons posi- 
tively asserts his belief that the consumption will be so great a 
century hence, but he startles us with such sentences as the follow- 
ing (already quoted) in italics :—‘“If owr consumption continue to 
multiply for 110 years at the same rate as hitherto, the total 
amount of coal consumed in the interval will be 100,000 millions 
of tons.” And we maintain, looking at the context, that it would 
have been just as sensible (or otherwise) if he had said that, should 
the demand for coal be further stimulated by our increasing 
prosperity, we might not have a pound of coal left m England 
twenty years hence! He devotes a whole chapter to the subject 
of the growth of our population, and we cannot find that he any- 
where compares it even with any hypothetical imcrease in the 
demand for coal. 
We do not pretend to express an original opinion as to the 
probable ratio in which our domestic demand is likely to increase. 
It would be absurd to do so. Already many of our cooking-ranges 
and stoves are heated with coal-gas. Fifty years hence they may all 
be heated with American or British petroleum gas, or any one of a 
score of old or new heat-producers ; and persons who deride the idea 
of coal substitutes (Mr. Jevons amongst the number), have no eyes 
for what is passing around them. Of this, more hereafter. All we 
can say is that, at present, calculating the domestic consumption at 
one ton per head of the population, we consume about 25,000,000 
tons annually ; and should the population of Great Britain be doubled 
or trebled during the next century, the steadicst item, compre- 
hending one-third of our whole consumption, may rise from 25 to 
