24 



A HISTORY OF 



combined, and kept inclosed, are produced 

 those various damps, that put on so many 

 dreadful forms, and are usually so fatal. 

 Sometimes those noxious vapours are per- 

 ceived by the delightful fragrance of their 

 smell," somewhat resembling the pea-blossom 

 in bloom, from whence one kind of damp has 

 its name. The miners are not deceived, 

 however, by its flattering appearances ; but 

 as they have thus timely notice of its coming, 

 they avoid it while it continues, which is gene- 

 rally during the whole summer season. Ano- 

 ther shows its approach by the burning of the 

 candles, which seem to collect their flame into 

 a globe of light, and thus gradually lessen, 

 till they are quite extinguished. From this, 

 also, the miners frequently escape ; however, 

 such as have the misfortune to be caught in 

 it, either swoon away, and are suffocated, or 

 slowly recover in excessive agonies. Here also 

 is a third, called the fulminating damp, much 

 more dangerous than either of the former, 

 as it strikes down all before it like a flash of 

 gunpowder, without giving any warning of its 

 approach. But there is another, more deadly 

 than all the rest, which is found in those places 

 where the vapour has been long confined, and 

 has been, by some accident, set free. The air 

 rushing out from thence, always goes upon 

 deadly errands ; and scarce any escape to 

 describe the symptoms of its operations. 



Some colliers in Scotland, working near an 

 old mine that had been long closed up, hap- 

 pened, inadvertently, to open a hole into it, 

 from the pit where they were then employed. 

 By great good fortune, they at that time, per- 

 ceived their error, and instantly fled for their 

 lives. The next day, however, they were re- 

 solved to renew their work in the same pit, 

 and eight of them ventured down, without any 

 great apprehensions ; but they had scarcely 

 got to the bottom of the stairs that led to the 

 pit, but, coming within the vapour, they all 

 instantly dropped down dead, as if they had 

 been shot. Amongst these unfortunate poor 

 men, there was one whose wife was informed 

 he was stifled in the mine ; and, as he hap- 

 pened to be next the entrance, she so far 

 ventured down as to see where he lay. As 

 ehe approached the place, the sight of her 



Phil. Trans, vol. ii. p. 375. 



husband inspired her with a drsire to rescue 

 him, if possible, from that dreadful situation; 

 though a little reflection might have shown 

 her it was then too late. But nothing could 

 deter her; she ventured forward, and had 

 scarce touched him with her hand, when the 

 damp prevailed, and the misguided, but faith- 

 ful creature, fell dead by his side. 



Thus, the vapours found beneath the sur- 

 face of the earth are very various in their ef- 

 fects upon the constitution : and they are not 

 less in their appearances. There are many 

 kinds that seemingly are no way prejudicial 

 to health, but in which the workmen breathe 

 freely; and yet in these, if a lighted candle be 

 introduced, they immediately take fire, and 

 the whole cavern at once becomes one furnace 

 of flame. In mines, therefore, subject to damps 

 of this kind, they are obliged to have recourse 

 to a very peculiar contrivance to supply suffi- 

 cient light for their operations. This is by a 

 great wheel ; the circumference of which is 

 beset with flints, which striking against steels 

 placed for that purpose at the extremity, a 

 stream of fire is produced, which affords light 

 enough, and yet which does not set fire to the 

 mineral vapour. 



Of this kind are the vapours of the mines 

 about Bristol : on the contrary, in other mines, 

 a single spark struck out from the collision of 

 flint and steel, would set the whole shaft in a 

 flame. In such, therefore, every precaution 

 is used to avoid a collision; the workmen 

 making use only of wooden instruments in 

 digging ; and being cautious, before they en- 

 ter the mine, to take out even the nails from 

 their shoes. Whence this strange difference 

 should arise, that the vapours of some mines 

 catch fire with a spark, and others only with 

 a flame, is a question that we must be content 

 to leave in obscurity, till we know more of 

 the nature both of mineral vapour and of fire 

 This only we may observe, that gunpowder 

 will readily fire with a spark, but not with the 

 flame of a candle ; on the other hand, spirits 

 of wine will flame with a candle, but not with 

 a spark : but even here the cause of this dif- 

 ference as yet remains a secret. 



As from this account of mines, it appears 

 that the internal parts of the globe are filled 

 with vapours of various kinds, it is not sur- 

 prising that they should, at different times, 



