The Life and Letters of Darwin, Volume 2 HTML version

1874 AND 1875.
[The year 1874 was given up to 'Insectivorous Plants,' with the exception of the months
devoted to the second edition of the 'Descent of Man,' and with the further exception of
the time given to a second edition of his 'Coral Reefs' (1874). The Preface to the latter
states that new facts have been added, the whole book revised, and "the latter chapters
almost rewritten." In the Appendix some account is given of Professor Semper's
objections, and this was the occasion of correspondence between that naturalist and my
father. In Professor Semper's volume, 'Animal Life' (one of the International Series), the
author calls attention to the subject in the following passage which I give in German, the
published English translation being, as it seems to me, incorrect: "Es scheint mir als ob er
in der zweiten Ausgabe seines allgemein bekannten Werks uber Korallenriffe einem
Irrthume uber meine Beobachtungen zum Opfer gefallen ist, indem er die Angaben, die
ich allerdings bisher immer nur sehr kurz gehalten hatte, vollstandig falsch
wiedergegeben hat."
The proof-sheets containing this passage were sent by Professor Semper to my father
before 'Animal Life' was published, and this was the occasion for the following letter,
which was afterwards published in Professor Semper's book.]
Down, October 2, 1879.
My dear Professor Semper,
I thank you for your extremely kind letter of the 19th, and for the proof- sheets. I believe
that I understand all, excepting one or two sentences, where my imperfect knowledge of
German has interfered. This is my sole and poor excuse for the mistake which I made in
the second edition of my 'Coral' book. Your account of the Pellew Islands is a fine
addition to our knowledge on coral reefs. I have very little to say on the subject, even if I
had formerly read your account and seen your maps, but had known nothing of the proofs
of recent elevation, and of your belief that the islands have not since subsided. I have no
doubt that I should have considered them as formed during subsidence. But I should have
been much troubled in my mind by the sea not being so deep as it usually is round atolls,
and by the reef on one side sloping so gradually beneath the sea; for this latter fact, as far
as my memory serves me, is a very unusual and almost unparalleled case. I always
foresaw that a bank at the proper depth beneath the surface would give rise to a reef
which could not be distinguished from an atoll, formed during subsidence. I must still
adhere to my opinion that the atolls and barrier reefs in the middle of the Pacific and
Indian Oceans indicate subsidence; but I fully agree with you that such cases as that of
the Pellew Islands, if of at all frequent occurrence, would make my general conclusions
of very little value. Future observers must decide between us. It will be a strange fact if