them. If this cooling still remain an unsolved
problem, its effects are perfectly appreciable.
The result was the annihilation of organic life
in the northern and central parts of Europe.
All the water-courses, the rivers and rivulets,
the seas and lakes, were frozen. As Agassiz
says in his first work on Glaciers, "A vast
mantle of ice and snow covered the plains, the
plateaus, and the seas. All the sources were
dried up: the rivers ceased to flow. To the
motions of a numerous and animated creation
the silence of death must have succeeded.
Great numbers of animals perished from cold.
The elephant and rhinoceros were killed by
thousands in the bosom of their grazing-
grounds, and were thus effaced from the list of
living creatures. Other animals also were over-
whelmed, but their race did not entirely perish."

To attain a full and clear belief that such
things really did occur, it is necessary to visit,
at least in idea, a country where glaciers still
exist. We shall then discover that the glaciers
of Switzerland and Savoy have not always been
confined to their present limits, and that they
are only miniature resemblances of the gigantic
glaciers of other times. And (Professor Tyndall
informs us) not in Switzerland alone—not
alone in proximity with existing glaciers—are the
well-known vestiges of ancient ice discernible;
on the hills of Cumberland they are almost
as clear as among the Alps. Round about
Scawfell, the traces of ancient ice appear, both
in rounded hog-backed rocks and in blocks
perched on eminences; and there are ample
facts to show that Borrodale was once occupied
by glacier ice. In North Wales, also, the
ancient glaciers have placed their stamp so
firmly on the rocks, that the ages which have
since elapsed have failed to obliterate even their
superficial marks. All round Snowdon these
evidences abound. The ground occupied by
the Upper Lake of Killarney was entirely
covered by the ancient ice, and every island that
now emerges from its surface is a glacier-dome.
North America is also thus glaciated. But the
most notable observation, in connexion with
this subject, is one recently made by Dr. Hooker
during a visit to Syria. He has found that the
celebrated cedars of Lebanon grow upon ancient
glacier moraines or trains of broken rock that
had fallen on the ice and been carried by it to
a lower level.

While stating these facts, the professor
suggests the most probable clue to their
explanation. To determine the conditions which
permitted the formation of those vast masses of
ice, the aim of all writers who have treated the
subject has been the attainment of cold. Some
eminent men have thought that the reduction
of temperature during the glacier epoch was
due to a temporary diminution of solar
radiation; others, that, in its motion through space,
our system may have traversed regions of low
temperature, and that, during its passage through
those regions, the ancient glaciers were
produced. Others have sought to lower the
temperature by a redistribution of land and water.
But the fact seems to have been overlooked,
that the enormous extension of glaciers in
bygone ages demonstrates, just as rigidly, the
operation of heat as the action of cold.

Cold alone will not produce glaciers. You
may have the bitterest north-east winds here in
London throughout the winter, without a single
flake of snow. Cold must have the fitting object
to operate upon; and this object—the aqueous
vapour of the air—is the direct product of heat.
But by directing our speculations to account
for the high temperature of the glacial epoch, a
complete reversal of some of the above-quoted
hypotheses would in all probability ensue. It
is perfectly manifest that, by weakening the
sun's action, either through a defect of emission
or by the steeping of the entire solar system,
in space of a low temperature, we should be
cutting off the glaciers at their source. In a
distilling apparatus, if you required to augment
the quantity distilled, you would not surely
attempt to obtain the low temperature necessary
to condensation, by taking the fire from under
your boiler; but this is what is done by those
philosophers who produce the ancient glaciers
by diminishing the sun's heat. It is clear
that the thing most needed to produce the
glaciers is an improved condenser. We cannot
afford to lose an iota of solar action; we need, if
anything, more vapour; but we need a condenser
so powerful, that this vapour, instead of
falling to the earth in liquid showers, shall be
so far reduced in temperature as to descend in
snow.

It was only after the glacial period, when the
earth had resumed its normal temperature, that
man was created. Whence came he?

He came—M. Figuier answers—whence the
first blade of grass which grew upon the
burning rocks of the Silurian seas came; whence
came the different races of animals which have
from time to time replaced each other upon the
globe, gradually rising in the scale of perfection.
He emanated from the will of the Author of the
worlds which constitute the universe.

We conclude with a few concluding sentences
of M. Figuier's Epilogue relative to a problem
for which neither induction nor analogy furnishes
us with any clue—namely, the perpetuity of our
species. Is man doomed to disappear from the
earth one day, as all the races of animals which
preceded him, and prepared the way for his
coming, have done? Or, may we believe that
man, gifted with the attribute of reason, stamped
with the divine seal, is to be the last supreme
end of creation?

As he has dared to say "I do not know," so
here he reverently states "I will not presume
to guess." Science cannot pronounce upon
these grave questions, which exceed the
competence and go beyond the circle of human
reasoning.

During the primitive epoch, the mineral kingdom
existed alone; the rocks, silent and solitary,
were all that was yet formed of the burning
earth. During the transition epoch, the
vegetable kingdom, newly created, extended itself