890 Mr Anderson on the Illuminating Power of CoahGa^ 
By examining the credit-side of the account, it may be infer-^ 
red that the same extent and degree of illumination, which, in> 
the case of coal-gas, costs the consumer L. 1513, 10s., could not 
be procured by means of tallow-candles for less than L. 10,114^ 
ISs., supposing a candle (four in the pound) to burn 12 hours, 
and the price to be lOd. per lb. ; being a saving of nearly 7 to 1 
in favour of coal-gas. The prime cost of the oil alone, to afford 
the same extent and degree of illumination, would be L 1453^,- 
^ 10s. ; admitting, on the statement of Taylor and Martineau, 
that 1 cubic feet of oil-gas yield a light, for an hour, equal to 
10 candles, and that a gallon of oil at 2s. gives by decomposi- 
tion 100 cubic feet of gas. 
On the other hand, if 1000 cubic feet of oil-gas be supposed 
to cost 26s., the price at which it is stated to be obtained in oil- 
gas manufactories, the expence of a quantity of oil-gas, equal in 
illuminating power to the quantity of coal-gas above mentioned, 
would be L. 1820. Hence the prime cost of the oil-gas would 
exceed the selling price of an equivalent quantity of coal-gas, 
produced at an establishment such as I have sketched, by more 
than the interest of the capital vested in the manufactory. 
If from these pecuniary views, which have a reference, in 
some measure, to the private interest of gas companies, we pass 
to considerations of a public and more comprehensive nature, 
and inquire which of the two rival gas manufactories ought to 
be encouraged on the ground of national policy, an enlightened 
Legislature, it may be presumed, could have no hesitation about 
giving the preference to coal-gas. It appears, indeed, that, so 
far as economy is concerned, the prices at which the two gases 
can be procured scarcely admit of comparison. Coal, the sub- 
stance from which one of them is evolved, is an article so very 
‘ abundant in this country, that any increase in the demand for 
it, so far from raising its price, would probably render it cheaper, 
in consequence of the improvements that might be expected to 
result from more extended woi'hlngs ; whereas oil, the substance 
from which the other is obtained, must always be limited in 
quantity, as well as precarious in supply. The very extension 
of oil-gas establishments would enhance its price, and set bounds 
to its use. Moreover, in the case of coal-gas, we obtain a pro- 
duct which is vastly more valuable than the raw material from 
