2 Sir Humphry Davy on the fire-damp of coal mines , and on 
and I have particular obligations on this point to the Rev. 
Dr. Gray, Cuthbert Ellison, Esq. M. P., the Rev. John 
Hodgson, Mr. Buddle, and Mr. Dunn. Dr. Fenwick, Dr. 
Clanny, and Mr. Fenwick, likewise kindly offered me their 
assistance. 
From the information which I collected on the spot, in- 
creased by the perusal of a report of Mr. Buddle on the 
state of the mines, I was convinced that, as far as ventilation 
was concerned, the resources of modern science had been 
fully employed ; and that a mode of preventing accidents 
was only to be sought for, in a method of lighting the mines 
free from danger, and which, by indicating the state of the 
air in the part of the mine where inflammable air was disen- 
gaged, so as to render the atmosphere explosive, should 
oblige the miners to retire till the workings were properly 
cleared. 
An account of an ingenious apparatus for burning a candle 
supplied with atmospherical air by a bellows through water, 
has been published in the Philosophical Transactions, by Dr. 
Clanny ; but I believe this apparatus has not yet been used 
in any of the collieries. 
The common means employed for lighting those parts of 
the mine where danger is apprehended from the fire-damp, 
is by a steel wheel, which, being made to revolve in contact 
with flint, affords a succession of sparks : but this apparatus 
always requires a person to work it; and, though much less 
liable to explode the fire-damp than a common candle, yet it 
is said to be not entirely free from danger. 
Mr. Buddle having obligingly shown to me the degree of 
light required for working the collieries, I made several ex- 
