LEAD. 
543 
the former has not been ascertained; yet we have 
reason to believe that this is incorrect, and that its 
actual depth, in standing water, is about three hun- 
dred and twenty feet. There cannot, however, be 
a doubt, but that this abyss has communication 
with others, still more deeply situated in the bow- 
els of the mountain, and into which the precipi- 
tated rubbish has found a passage. The superfluous 
water of the level falls through a water-gate into 
this profound caldron, with a noise like a rushing 
torrent. 
The fissure is calculated at about two hundred 
and eighty yards below the surface of the moun- 
tain ; and so great is its reach upwards, that rockets 
of sufficient strength to ascend four hundred and 
fifty feet have been fired without rendering the 
roof visible. The effect of a Bengal light discharged 
in this stupendous cavity is extremely magnificent 
and interesting. Beyond the fissure the level has 
been driven to a similar length to that part which 
precedes it ; but in this division of its course little 
occurs to excite observation. 
Among the different lead-mines in England may 
be mentioned those in the Mendip hills in Somer- 
setshire, which have long continued to yield con- 
siderable quantities of ore. 
France produces lead in great abundance, thirty 
thousand quintals being annually raised, according 
to the Journal des Mines , in the different depart- 
ments: — two-thirds of this quantity is extracted from 
