THE FIRE-DAMP'S FAMILY CIRCLE. 189 



the first station, and beaten against the roof of the coal and 

 sides of the posts, and lay afterwards a good while senseless. 

 As it drew up the day-pit, it caught one of the men along 

 with it that was next the eye, and up it comes with such a 

 terrible crack, not unlike but more shrill than a canon, that 

 it was heard fifteen miles off along with the wind, and such a 

 pillar of smoke as darkened all the sky overhead for a good 

 while. The brow of the hill above the pit was eighteen yards 

 high, and on it grew trees fourteen or fifteen yards long ; yet 

 the man's body and other things from the pit were seen above 

 the highest trees at least a hundred yards.' 



Though the fire-damp proved mischievous almost from the 

 first period when coal-mines were worked in Great Britain, 

 yet not until the middle of the eighteenth century did it 

 begin to commit ravages on a large scale. As coal-workings 

 up to that time were small, accumulations of gas could not so 

 readily take place. It was natural that miners, so continually 

 exposed as they were to the attacks of invisible enemies, 

 should try to discover their qualities, their composition and 

 analogies. I pass over, as altogether unworthy of serious 

 notice, the vague speculations on this matter during the 

 seventeenth century : for though Van Helmont in the begin- 

 ning of that epoch suspected the existence of other gaseous 

 fluids than air though he applied to them the designation 

 gas, and at a still later period individualised, under the name 

 of gas sylvestre, our present carbonic acid gas ; though, more, 

 in his treatise De Flatibus he mentioned that the gas pro- 

 duced from animal digestion, and liberated by proper con- 

 trivances into the flame of a candle, would take fire and 

 burn; yet a systematic examination of gaseous bodies was 

 altogether beyond the means of philosophers : indeed, Van 

 Helmont seemed half inclined to consider gases as a sort of 

 quasi spirits partly spiritual, partly immaterial, having the 

 qualities of both. 



Towards the middle of the eighteenth century, and con- 



