Reviews—Jevons—On The Coal Question. 551 
stances’ (p. 103), such-as the substitution of machinery for hand 
labour, the reduction of taxes, and low rates of profit, which have 
respectively tended to the increase of employment for workmen, to 
the increase of consumption of the articles taxed and the consequent 
addition to the revenue, and to the increase of business. ‘The same 
principles apply, with even greater force and distinctness, to the use 
of such a general agent as coal. It is the very economy of its use 
which leads to its extensive consumption. It has been so in the past 
and it will be so in the future’ (p. 10+). Thus the steam-engine 
was hardly used at all for many years after its invention, on account 
of the large quantity of coal consumed ; and it did not come into 
general use until Watt brought forward his inventions for saving 
heat, that is coal. 
Our author also shows that we cannot look forward to finding any 
substitutes for coal, and remarks that ‘if any wholly new source of 
power be some day discovered, we have no reason to suppose that 
a a will be as pre-eminently endowed with it as with coal’ 
p: 144). 
‘Another reason for our looking forward to a great increase in the 
consumption of coal is that ‘we do each of us in general increase 
our consumption. . . . The population has about doubled since the 
beginning of the century, but the consumption of coal has increased 
eightfold and more. The consumption per head of the population 
has therefore increased fourfold’ (p. 150). 
Having found that the average yearly growth of our consumption 
is 34 per cent., and assuming this rate of growth to hold in the fu- 
ture, it follows that the increase will be from 83°6 millions of tons 
in 1861 to 2,607°5 millions of tons in 1961, and ‘ the total aggregate 
consumption of the period of 110 years, 1861—1970, would be 
102,704,000,000 tons . . or inround numbers . . if our consumption 
of coal continue to multiply for 110 years at the same rate as hither- 
to, the total amount of coal consumed in the interval will be one hun- 
dred thousand million tons. Mr. Hull’s estimate of the available coal 
in the kingdom, within a depth of 4,000 feet, is only 83,000,000,000 
tons; and therefore ‘ rather more than a century of our present pro- 
gress would exhaust our mines to the depth of 4,000 feet, or 1,500 
feet deeper than our present mines’ (pp. 213-5)—a pleasing prospect 
truly! Of course, it matters little to Mr. Jevons’s calculation 
whether Mr. Hull’s estimate is a few thousand millions of tons too 
low or not. 
Our author next shows most conclusively that it is absurd to think, 
or rather to dream, that when our coal is getting exhausted we shall 
be able to import coal from other lands to work our factories: ‘ about 
1,200 colliers of the size of the Great Eastern would be required to 
maintain our present supplies only’ (p. 225), and the cost of freight 
would be very heavy. Of course, the raw materials would then, as 
now, go to the coal-yielding country to be worked up; it is com- 
mercially impossible that we should import both coal and raw ma- 
terials. This side of the question is strangely illustrated by ‘the 
curious fact that about the end of the seventeenth century the iron 
