connexion with certain comets, and the perplexing questions
suggested by the Solar Corona and the Zodiacal light, and it will
be seen that our knowledge is in a transitional state; that with
so many problems unsolved, any apparent contradiction to the
sacred record will require a careful scrutiny to ascertain that
the grounds on which it is brought forward are well established.

Geology, so far as our present subject is concerned, stands upon a
somewhat different footing. Though a much younger science than
astronomy, it has one great advantage over it; the facts with
which it has to do are for the most part discernible by the
unaided senses, and it is therefore independent of instrumental
help. Many changes have occurred in the views of Geologists, but
in the main they have reference to processes [Footnote: Such, for
instance, is the modification of the views of geologists as to the
relative effects of "disruption" and "denudation" in determining
the features of the earth's surface.] rather than to results, and
it is the results with which we are chiefly concerned.

Physiologists have entered on the contest with the Bible on two
different, and seemingly contradictory grounds. Some of them have
maintained that the varieties of mankind are so distinct, that it
is impossible they can all be descended from a single human pair,
while others assert that not only all the varieties of mankind,
but all the varieties of living beings are descended from a single
progenitor. Between the advocates of these two systems there must
be such an enormous difference as to the extent to which variation
is possible, as to justify us in assuming that the fundamental
principles of physiological science are not yet satisfactorily
ascertained.