370 Trial of Di. Reid’ Clanny’s Lamp (May, 
perfect safety. I was also told that frequently large masses of coal 
are struck off from the sides of the mine, whilst the pitmen are 
hewing out the coal, as | have witnessed myself; and should a 
piece of coal strike the lamp upon the side, it would of course 
break it, and expose the inflammable gas to an instantaneous explo- 
sion. 
The lamps, as they are now constructed, have the following 
qualities. ‘The piece of glass in front is so strong as to be ensured 
to carry a ton weight. The rest of the lamp is copper, or strong 
block tin, supported by three strong iron pillars. 
The lamp is now constructed of so small a form, that it may be 
put into a great coat pocket. A copper lamp may be made for 
about 30s. or 35s.; and if it be of block tin, the expenses will not 
exceed half the latter sum. 
By means ef a very simple apparatus attached to the lamp, I can 
light the candle with a common match of hyper-oxymuriate of 
potash and concentrated sulphuric acid in an atmosphere of inflam- 
mable air. 
And should the lamp be upset (which can only be done wilfully), 
the candle is instantly extinguished. 
I can manage the bellows in such a way that the candle continues 
to burn with the fire-damp of most mines; and the syphon, which 
_may be understood by the engraving of my lamp in the Transactions 
of the Royal Society for 1813, is for the purpose of keeping the 
water upon a level within and without the lamp, while the candle 
continues to burn, though the inflammable air be at the firing 
oint. 
By a small piece of machinery, which costs about 20s., the 
bellows may be urged so as to give a constant and sufficient supply 
of air for the candle for two hours, without winding up; but if the 
proportion of inflammable air be very great, a slight explosion gene~ 
rally takes place within the lamp, which extinguishes the candle. 
When this latter circumstance occurs, the lamp is to be re-lighted, 
and air given to the candle in the following manner. To the valve 
of the bellows a leathern nose, or tube, is attached, which, being 
of such a length as to reach to that part of the mine where there is 
a current of good atmospheric air, by this means the lamp will of 
course continue to afford a clear light in the midst of inflammable 
air. 
It sometimes happens that there is a deficiency of oxygen in the 
atmosphere of a coal-mine. In those cases a very small taper may 
be usedin the lamp, the combustion of which may be supplied by a 
goat-skin full of atmospheric air, or afew bladders of oxygen gas. 
The enormous expense of steel-mills in some mines almost exceed 
belief. I am informed that in one working of a colliery in this 
neighbourhood, the expense of steel mills is about 30/. every fort- 
night; so many of them have to be kept at work at a time to give 
any thing like a sufficient light. 
