Wallace's letter to Darwin, dated January 1st, 1881, he evidently uses the
expression "passing through the air" in contradistinction to the migration
of a species by gradual extension of its area on land. "Through the air"
would moreover include occasional modes of transport other than simple
carriage by wind: e.g., the seeds might be carried by birds, either
attached to the feathers or to the mud on their feet, or in their crops or
intestines.)

I suppose it would be travelling too far (though for the geographical
section the discussion ought to be far-reaching), but I should like to see
the European or northern element in the Cape of Good Hope flora discussed.
I cannot swallow Wallace's view that European plants travelled down the
Andes, tenanted the hypothetical Antarctic continent (in which I quite
believe), and thence spread to South Australia and the Cape of Good Hope.

Moseley told me not long ago that he proposed to search at Kerguelen Land
the coal beds most carefully, and was absolutely forbidden to do so by Sir
W. Thomson, who said that he would undertake the work, and he never once
visited them. This puts me in a passion. I hope that you will keep to
your intention and make an address on distribution. Though I differ so
much from Wallace, his "Island Life" seems to me a wonderful book.

Farewell. I do hope that you may have a most prosperous journey. Give my
kindest remembrances to Asa Gray.



LETTER 398. TO J.D. HOOKER.
Down, August 12th, 1881.