404 INUNDATIONS IN THE NETHERLANDS. 
shire, by diking out the sea, and the rivers which traverse the 
fens of that country. 
The almost continued prevalence of west winds upon both 
coasts of the German Ocean occasions a constant set of the 
currents of that sea to the east, and both for this reason and 
on account of the greater violence of storms from the former 
quarter, the English shores of the North Sea are less exposed 
to invasion by the waves than those of the Netherlands and the 
provinces contiguous to them on the north. The old Nether- 
landish chronicles are filled with the most startling accounts 
of the damage done by the irruptions of the ocean, from west 
winds or extraordinarily high tides, at times long before any con- 
siderable extent of seacoast was diked. Several hundreds of 
these terrible inundations are recorded, and in many of them 
the loss of human lives is estimated as high as one hundred 
thousand. It is impossible to doubt that there must be enor- 
mous exaggeration in these numbers; for, with all the reckless 
hardihood shown by men in braving the dangers and priva- 
removed ; that the earth excavated in the construction of English railways up to 
that date amounted to a hundred and fifty million cubic yards, and that at 
the Round Down Cliff, near Dover, a single blast of nineteen thousand pounds 
of powder blew down a thousand million tons of chalk, and covered fifteen 
acres of land with the fragments. 
Tn 1869, a mass of marble equal to one and a half times the cubical contents 
of the Duomo at Florence, or about 450,000 cubic yards, was thrown down at 
Carrara by one blast, and two hours after, another equal mass, which had been 
loosened by the explosion, fell of itself.—ZOLFANELLI, La Lunigiana, p. 43. 
The coal yearly extracted from the mines of England averages not less than 
100,000,000 tons. The specific gravity of British coal ranges from 1.20 to 1.35, 
and consequently we may allow a cubic yard to the ton. If we add the earth 
and rock removed in order to reach the coal, we shall have a yearly amount of 
excavation for this one object equal to more than thirty times the volume of 
the pyramid of Cheops. 
These are wonderful achievements of human industry; but the rebuilding 
of Chicago within a single year after the great fire—not to speak of the extraor- 
dinary material improvements previously executed at that city—snurpasses 
them all, and it probably involved the expenditure of a sum of muscular and 
of moral energy which has never before been exerted in the accomplishment 
of a single material object, within a like period. 
