SUBMARINE MINES. $] 
required for the accommodation of shipping. Witness the 
Cyclopean grandeur of the Liverpool docks or of the Great Fioat 
at Birkenhead, which alone covers an area of water of 121 acres, 
and whose portals, with a clear opening of 100 feet, will admit 
the largest screw-steamer or sailing ship the wildest imagination 
has yet conceived. Six millions of money is the cost of this 
one work alone—more than would be required to raise a pyramid 
like that of Cheops—and even this sum isa trifle when com- 
pared with what has been spent on the harbours of Liverpool, 
London, and other great commercial cities. 
Not satisfied with erecting his lighthouses on wave-worn rocks 
or defying the waves with his colossal breakwaters, man spans 
bridges over arms of the sea and excavates mines under the 
abysses of the deep. The locomotive now rolls full speed 100 
feet above high water over the strait which separates Anglesea 
from the mainland; and in Botallack and several other Cornish 
mines the workman, while resting from his subterranean labours, 
hears the awful voice of the ocean rolling over his head. 
* In all these submarine mines,” says Mr. Henwood, “ I have 
heard the dashing of the billows and the grating of the shingle 
when in calm weather. I was once, however, underground in 
Wheal Cock during a storm. At the extremity of the level 
seaward some eighty or one hundred fathoms from the shore, 
little could be heard of its effects, except at intervals, when the 
reflux of some unusually large wave projected a pebble outward, 
bounding and rolling over the rocky bottom. But when standing 
beneath the base of the cliff, and in that part of the mine where 
but nine feet of rock stood between us and the ocean, the heavy 
roll of the large boulders, the ceaseless grinding of the pebbles, 
the fierce thundering of the billows, with the crackling and 
boiling as they rebounded, placed a tempest in its most appalling 
form too vividly before me ever to be forgotten. More than 
once doubting the protection of our rocky shield, we retreated 
in affright, and it was only after repeated trials that we had 
confidence to pursue our investigations.” Yet the miners, 
accustomed from their early youth to the fierce and threatening 
roaring of the stormy sea, pursue their work from year to year, 
never doubting that the thin roof which separates them from a 
watery grave will continue to protect them, as it has shielded 
their fathers before them. 
