A. Strahan — Explosive 8/icIcensidcs. 407 



we are used to hear ; after some little Discourse, they told me that 

 they had heard it very often, and (says thej') not long before you 

 came here, we was both at Work and heard a Noise, and we concluded 

 it could be nothing but somebody coming down the Shaft, and in a 

 little while, about the time they might be got to our first Sump-head, 

 we presently heard as we thought, them throwing the Corves down 

 the Sump ; we heard 'em rattle so plain against the hard Sides, and 

 amazed at such folly we came in hast up, where we found all things 

 as we had left them when we came down without the least alteration, 

 as we could discerne. Thus the Men. 



" One Instance more may be of the same hind, where I have been 

 acquainted, and 'tis this : I with others wrought in a certain Work 

 about eighty Yards deep, the Shaft was Sunk in a great and loose 

 Shack of Chirts, which sunk down to the Soles and much further 

 for any thing we know, being exceeding loose, and not any openess 

 seen throughout the whole Work, but the ways that were cut ; the 

 loosness of this Work was all the care to keep it up ; yet what I 

 Remark is, that the Workmen themselves, but more especially the 

 Labourers, at the Sump-heads and in the Gates, have been often 

 affrighted with such a Noise and dismal Eattle, as if sometimes the 

 Shaft had run in, and at other times the Gates or Sumps ; I have 

 heard it my self, and have thought by the Noise, we had been all 

 made fast, but by God's Blessing, never found one Stick of Timber 

 disordered or out of its Place ; one would think that the Noise 

 might be caused by something running in some openness, or great 

 Shack, but there was never any such seen in the whole Work ; for 

 altho' there were large and wild shaken Places, yet they were all 

 full of loose small Chirts to the Day ; . . . what these Noises are, 

 we miners know not, but must leave them to the Disquisition of such 

 learn'd Men as deal in those profound Matters ; I mention it because 

 Miners say that the Knocking is some Being, that Inhabits in the 

 Concaves and Hollows of the Earth ; and that it is thus kind to 

 some Men of suitable Tempers, and directs them to the Ore by such 

 its knocking, etc." 



In some of the mines near Eyam, which have been referred to 

 above, explosions of fire-damp have occurred from time to time, 

 especially in those which were sunk through the Yoredale Shale into 

 the Carboniferous Limestone, and in the water-levels which were 

 driven long distances through the Millstone Grit and Yoredale Shale 

 to drain the mines. References to such explosions occur in most of 

 the authors quoted above, and in such terms as to show that they 

 were clearly recognized as distinct from the explosions due to slicken- 

 sides. I am therefore disposed to believe that the great explosion 

 described by Whitehurst as having occurred in 1738 was due to 

 slicken sides, but that in the fifty years which had elapsed before 

 Whitehurst wrote, the account of the effects had become considerably 

 exaggerated, or more probably confused with the account of some 

 explosion due to fire-damp. 



It is difficult to understand the lifting of the barrel in the shaft, 

 and the blowing of a man twelve fathoms perpendicularly, except 



