and there was no fireplace, diffusion through the walls would change
the entire air once an hour, so that the percentage would not rise
above 0.04; while in any ordinary room imperfect workmanship and an
open chimney would change it four times in the hour, reducing the
percentage to 0.01, a quantity which the most inveterate enemy of
water gas could not claim would do more than produce a bad headache,
an ailment quite as likely to have been caused by the same factor that
brought about the blowing out of the gas.

Moreover, we are now talking about the use of carbureted water gas as
an enricher of coal gas, and not as an illuminant to be consumed _per
se._ and we may calculate that it would be probably used to enrich a
16-candle coal gas up to 17.5 candle power. To do this 25 per cent. of
22 candle power carbureted water gas would have to be mixed with it,
and taking the percentage of carbon monoxide in London gas at 5 per
cent.--a very fair average figure--and 18 per cent. as the amount
present in the Van Steenbergh gas, we have 8.25 per cent. of carbon
monoxide in the gas as sent out--a percentage hardly exceeding that
which is found in the rich cannel gas supplied to such towns as
Glasgow, where I am not aware of an unusual number of deaths occurring
from carbon monoxide poisoning.

The carbureted water gas has a smell every bit as strong as coal gas,
and a leak would be detected with equal facility by the nose; and I
think you will agree with me that the cry raised against the use of
carbureted water gas, for this reason, is one of the same character
that hampered the introduction of coal gas itself at the commencement
of this century.

We must now turn to the chemical actions which are taking place in the