ll or Huxley by speaking to them of _their_ objections,
and giving me as the authority for so affiliating them.--Very truly
yours,

HERBERT SPENCER.

* * * * *

SIR C. LYELL TO A.R. WALLACE

_73 Harley Street, London, W. November, 1867._

Dear Wallace,--You probably remember an article by Agassiz in an
American periodical, the _Christian Observer_, on the diversity of human
races, etc., to prove that each distinct race was originally created for
each zoological and botanical province. But while he makes out a good
case for the circumscription of the principal races to distinct
provinces, he evades in a singular manner the community of the Red
Indian race to North and South America. He takes pains to show that the
same American race pervades North and South America, or at least all
America south of the Arctic region. This was Dr. Morton's opinion, and
is, I suppose, not to be gainsaid. In other words, while the Papuan,
Indo-Malayan, Negro and other races are strictly limited each of them to
a particular region of mammalia, the Red Indian type is common to
Sclater's Neo-arctic and Neo-tropical regions. Have you ever considered
the explanation of this fact on Darwinian principles? If there were not
barbarous tribes like the Fuegians, one might imagine America to have
been peopled when mankind was somewhat more advanced and more capable of
diffusing itself over an entire continent. But I cannot well understand
why isolation such as accompanies a very low state of social progress
did not cause the Neo-tropical and Neo-arctic regions to produce by
varieties and Natural Selection two very different human races. May it
be owing to the smaller lapse of time, which time, nevertheless, was
sufficient to allow of the spread of the representatives of one and the
same type from Canada to Cape Horn? Have you ever touched on this
subject, or can you refer me to anyone who has?--Believe me ever most
truly yours,

CHA. LYELL.

* * * * *

TO SIR C. LYELL

1867.

Dear Sir Charles,--Why the colour of man is sometimes constant over
large areas while in other cases it varies, we cannot certainly tell;
but we may well suppose it to be due to its being more or less
correlated with constitutional characters favourable to life. By far the
most common colour of man is a warm brown, not very different from that
of the American Indian. White and black are alike deviation