102 Mr Bald on the Fires that take place in Collieries. 



The first species of gas is comparatively easily guarded against 

 and avoided ; the latter is subtile, — the very pestilence and bane 

 of the miners, — springs into action as instantly as the lightning 

 of heaven, producing the most fearful destruction, and the most 

 appalling catastrophes, sweeping before it men, horses, and ma- 

 terials, like chaff before the wind, in one mingled mass of horri- 

 ble ruin. 



These disasters, though violent and dreadful, are happily of 

 short duration ; and the bold, unyielding, and persevering spirit 

 of the miner, in a short time repairs the wreck ; the labours are 

 resumed as if no such disaster had taken place, and that with a 

 degree of cheerfulness which has greatly surprised every one. 



There is, however, an accident of a different kind from these 

 before mentioned, which, though in general very slow in its pro- 

 gress, is most difficult to overcome, because, though slow in 

 progress, it goes on unremittingly, gains strength hour after 

 hour, and day after day, and, in many instances, puts the skill 

 and persevering exertions of the miner to defiance; — this is, 

 common burning fire in the coal mines, the ignition of the coal. 



This fire arises from three causes : 1 st, From the flame of a 

 blower in the coal, from which the carburetted hydrogen issues 

 with such violence, and in such quantity, that the noise is fully 

 louder than the noise of steam issuing from the valve of a steam- 

 engine boiler, when fully opened, and steam in abundance with- 

 in the boiler ; or, by the blast of an explosion, which is a maga- 

 zine of blue and white flame, of intense heat, which sets fire to 

 the small coal-dust of the roads in the mines; for this fiery blast 

 never sets on fire the solid coal, though the blower does so in 

 some instances ; ^dli/, From spontaneous ignition, which is the 

 most common, arising from the decomposition of pyrites amongst 

 the coal rubbish ; for, however abundant the pyrites be among the 

 solid strata, and though in contact with water, no decomposition 

 takes place, but, in the loose rubbish, the contact of air will soon 

 produce fire, particularly if aided by the contact of water or 

 moisture ; 3J/^, From accident and inadvertency by the contact 

 of common fire with the solid coal, or with the coal rubbish. 



For the extinguishing of these fires several methods are in 

 practice. In some instances, the fire, if not of great extent, or 

 only very recent, can be put out by throwing water upon the 

 burning mass ; but if pyrites abound, the application of water 



