ty of these mines from carburetted hydrogen gas,
which exempts them from the danger of explosion. But though there be no
explosive gas, there is generated, to a certain extent, in the more
remote recesses of the pit, carbonic acid and other gases, producing the
most injurious effects--impairing the constitution by slow degrees, and
along with the more direct cause (the smoke from the lamp, candle, and
the product of the combustion of gunpowder,) making progressive inroads
on the health of the unfortunate miner. And how, I ask, can it be
otherwise, in such circumstances? So long as it is possible for him to
go on--so long as there is air enough to support the combustion of the
lamp or candle, the labourer must proceed with his toil. I say, from
there being no fire-damp, less attention is paid to ventilation, and it
is a common occurrence with colliers in these localities, to be obliged
to leave their work, from there not being a sufficiency of oxygen to
keep their lights burning, and support respiration; and this temporary
cessation of labour under such circumstances is regarded as a hardship
by some proprietors, while the bodily sufferings of the miner, shut up
and necessitated to labour in this situation, are little considered.

After labouring beyond a given time in those confined situations, there
is a much freer action of the respiratory apparatus, the oxygen is
considerably exhausted, and to make up for this deficiency, the volume
of air inspired, (impure though it be,) is much greater. Every now and
then, there is a disposition to draw a deep breath, followed by a
peculiar and gradual decrease of strength. Therefore, in these forcible
expansions of the chest, it is to be expected that a considerable
quantity of the floating carbon will be conveyed to the cellular tissue.

The atmosphere of the coal mine at length becomes so vitiated, by the
removal of the oxygen in breathing, and the substitution of carbonic
acid, that the respiration becomes gradually more difficult, and the
exhausted labourer has ultimately to retire from the pit, as there is no
other mode by which the noxious air can be removed--owing to the
underground apartments being so small--than by gradually allowing purer
air to accumulate. The miner is thus enabled to return to his
employment.

It is about thirty years since miners in this district adopted the use
of coarse linseed oil, instead of whale oil, to burn in their lamps; and
it is very gene