To F. T. Köppen 28 April [1871]
Summary
Thanks for FTK’s locust paper ["Die geographische Verbreitung der Wanderheuschrecke", Petermann’s Geogr. Mittheil. (1871)].
| Author: | Charles Robert Darwin |
| Addressee: | Friedrich Theodor Köppen (Fedor Petrovich Keppen) |
| Date: | 28 Apr [1871] |
| Classmark: | Archive of the Russian Academy of Sciences, St Petersburg branch: SPBB ARAS (Fond 92. Register 1. Folder 112. P. 1, 1 r) |
| Letter no: | DCP-LETT-7723 |
To F. T. Köppen 18 November 1874
Summary
Thanks FTK for telling him of Jahn’s work [see 9719], of which CD had not heard. It would have been of greatest use in writing Descent.
| Author: | Charles Robert Darwin |
| Addressee: | Friedrich Theodor Köppen (Fedor Petrovich Keppen) |
| Date: | 18 Nov 1874 |
| Classmark: | Archive of the Russian Academy of Sciences, St Petersburg branch: SPBB ARAS (Fond 92. Register 1. Folder 112. P. 3, 3 r) |
| Letter no: | DCP-LETT-9722 |
From F. T. Köppen 25 April 1871
Summary
Sends his paper on locusts ["Die geographische Verbreitung der Wanderheuschrecke", Petermann’s Geogr. Mittheil. (1871)]. The effect of the growth of forest land on their increase; meteorological and climatic effects.
Also observations made on increase in mice as a result of increase of locusts, on whose eggs they fed, and of increase of weasels that fed on mice.
| Author: | Friedrich Theodor Köppen (Fedor Petrovich Keppen) |
| Addressee: | Charles Robert Darwin |
| Date: | 25 Apr 1871 |
| Classmark: | DAR 46.1: 102 |
| Letter no: | DCP-LETT-7716 |
From F. T. Köppen 13 November 1874
Summary
Calls CD’s attention to a book that deals with subjects related to both Descent and Expression: Ferdinand Jahn, Die abnormen Zustände des menschlichen Lebens als Nachbildungen und Wiederholungen normaler Zustände des Thierlebens [1842].
| Author: | Friedrich Theodor Köppen (Fedor Petrovich Keppen) |
| Addressee: | Charles Robert Darwin |
| Date: | 13 Nov 1874 |
| Classmark: | DAR 91: 84 |
| Letter no: | DCP-LETT-9719 |
| letter | (4) |
| Darwin, C. R. | (2) |
| Köppen, F. T. | (2) |
| Darwin, C. R. | (2) |
| Köppen, F. T. | (2) |
