102 The President's Address.
geologists, but Mr. Wallace has now given weighty reasons
for believing that this explanation is inadequate, and that
purely astronomical causes are insufficient to account for
such great climatic changes. He is of opinion that certain
concomitant geographical changes are also necessary, and
he thus adds to Croll's astronomical theory a modification
of the purely geographical explanation of climatic change
long ago advanced by Sir Charles Lyell in the "Principles
of Geology." The history of science presents many such
instances of the amalgamation of hypotheses. A theory
may for a long time be maintained until some new and
more perfect theory is offered in its place—in the heat of
intellectual excitement the older theory is rejected under
the belief that the newer one has rendered it unnecessary,
but in the course of time it is seen that the two are not
necessarily mutually exclusive, and some master worker
shows that they are both requisite for an adequate expla-
nation of the phenomena concerned.
The Field Meeting held on the 3rd of July, when Major-
General Pitt-Rivers gave us the benefit of his large
experience on the occasion of our visit to the ancient earth-
works in the Forest, has opened up a line of work which
may enable our Club to do substantial service to
archaeology. At this meeting, in addition to our conductor,
we had with us Mr. W. L. Distant, one of the directors of
the Anthropological Institute; Mr. B. H. Cowper, the
discoverer of the Loughton Camp ; and Mr. D'Oyley, the
surveyor of the earthworks; to these gentlemen the thanks
of the Club are due. The history of these camps is quite
unknown, and their supposed founders come down to us
only through uncertain traditions which are valueless to the
scientific archaeologist. At the suggestion of our conductor
we therefore determined to attempt to settle the problem,
by raising an "Exploration Fund" for the purpose of open-
ing these earthworks, with a view to obtaining some relics
of their constructors. I have already had the pleasure of
informing you that the necessary permission has been
granted by the Forest Conservators, and the thanks of the
Club have been rendered to this body, and to our esteemed