scientific conceptions, in the shape of essays on such trifles as "the
Nature of Life" and the "Origin of All Things," which reach me, from time
to time, might well be bound up with them.


The tenth essay in this volume unfortunately brought me, I will not say
into collision, but into a position of critical remonstrance with regard
to some charges of physical heterodoxy, brought by my distinguished
friend Lord Kelvin, against British Geology. As President of the
Geological Society of London at that time (1869), I thought I might
venture to plead that we were not such heretics as we seemed to be; and
that, even if we were, recantation would not affect the question of
evolution.

I am glad to see that Lord Kelvin has just reprinted his reply to my
plea,[1] and I refer the reader to it. I shall not presume to question
anything, that on such ripe consideration, Lord Kelvin has to say upon
the physical problems involved. But I may remark that no one can have
asserted more strongly than I have done, the necessity of looking to
physics and mathematics, for help in regard to the earliest history of
the globe. (See pp. 108 and 109 of this volume.)

[Footnote 1: _Popular Lectures and Addresses._ II. Macmillan and Co.
1894.]

And I take the opportunity of repeating the opinion, that, whether what
we call geological time has the lower limit assigned to it by Lord
Kelvin, or the higher assumed by other philosophers; whether the germs of
all living things have originated in the globe itself, or whether they
have been imported on, or in, meteorites from without, the problem of the