43." I., "Flora Antarctica." 2
volumes, London, 1844-47.), and yet I declare I do not know what
precise facts I could refer you to. Bronn's "Geschichte" (557/6.
"Naturgeschichte der drei Reiche." H.E. Bronn, Stuttgart, 1834-49.)
which you once borrowed) is the only systematic book I have met with on
such subjects; and there are no general views in such parts as I have
read, but an immense accumulation of references, very useful to follow
up, but not credible in themselves: thus he gives hybrids from ducks and
fowls just as readily as between fowls and pheasants! You can have it
again if you like. I have no doubt Forbes' essay, which is, I suppose,
now fairly out, will be very good under geographical head. (557/7. "On
the Connection between the Distribution of the existing Fauna and Flora
of the British Isles, and the Geological Changes which have affected
their Area, especially during the Epoch of the Northern Drift," by E.
Forbes. "Memoirs of Geological Survey," Volume I., page 336, 1846.)
Kolreuter's German book is excellent on hybrids, but it will cost you a
good deal of time to work out any conclusion from his numerous details.
(557/8. Joseph Gottlieb Kolreuter's "Vorlaufige Nachricht von eininigen
das Geschlecht der Pflanzen betreffenden Versuchen und Beobachtungen."
Leipzig, 1761.) With respect to variation I have found nothing--but
minute details scattered over scores of volumes. But I will look over
Book III. again. What a quantity of work you have in hand! I almost wish
you could have finished America, and thus have allowed yourself rather
more time for the old "Principles"; and I am quite surprised that you
could possibly have worked your own new matter in within six weeks. Your
intention of being in Southampton will much strengthen mine, and I shall
be very glad to hear some of your American Geology news.

LETTER 558. TO L. HORNER. Down, Sunday [January 1847].

Your most agreeable praise of my book is enough to turn my head; I am
really surprised at it, but shall swallow it with very much gusto...
(558/1. "Geological Observations in S. America," London, 1846.)

E. de Beaumont measured the inclination with a sextant and artificial
horizon, just as you take the height of the sun for latitude.

With respect to my Journal, I think the sketches in the second edition
(558/2. "Journal of Researches into the Natural History and Geology of
the Countries visited during the Voyage of H.M.S. 'Beagle.'" Edition II.
L