was somewhat inadequate; the theory then prevailing being that bogs owed
their origin not to water alone, but to the destruction of woods, whose
remains are found imbedded in them--a view which held good for another
fifty or sixty years, until it was in its turn effectually disposed of
by the report of the Bogs Commission in 1810, when it was proved once
for all that it was to the growth of sphagnums and other peat-producing
mosses they were in the main due--a view which has never since been
called in question.

A great deal, however, had happened to Ireland before the bogs began to
grow on it at all. It had--to speak only of some of its later
vicissitudes--been twice at least united to England, and through it with
what we now know as the continent of Europe, and twice severed from it
again. It had been exposed to a cold so intense as to bleach off all
life from its surface, utterly depriving it of vegetation, and grinding
the mountains down to that scraped bun-like outline which so many of
them still retain; had covered the whole country, highlands and lowlands
alike, with a dense overtoppling cap of snow, towering often thousands
of feet above the present height of the mountains, from which "central
silence" the glaciers crept sleepily down the ravines and valleys,
eating their way steadily seaward, and leaving behind them moraines to
mark their passage, leaving also longitudinal scratches, cut, as a
diamond cuts glass, upon the rocks, as may be seen by any one who takes
the trouble of looking for them; finally reaching the sea in a vast
sloping plateau which pushed its course steadily onward until its
further advance was overborne by the buoyancy of the salt water, the
ends breaking off, as the Greenland glaciers do to-day, into huge
floating icebergs, which butted against one another, jammed up all the
smaller bays and fiords; were carried in again and again on the rising
tide; rolled hither and thither like so many colossal ninepins; played,