journal, an assertion that the earth's axis had at one time been
at right angles to the ecliptic, that it had slowly inclined, as
we see a spinning top incline, till it had reached an angle of
45° or more, and was now half-way back to the perpendicular.
This, if true, would explain all the changes of climate which
the north part of Europe has evidently passed through from
tropical heat to the cold of the glacier epoch. It would ex-
plain the plants in those coal-measures. It would explain
everything, if true? But is it true? How many times must
we outsiders learn up our science, and then unlearn it? Each
new generation of philosophers laughs at the conclusions of
its predecessors.

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