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Darwin Correspondence Project

To Christian Karl Josias Bunsen1   16 August [1853]2

Down Bromley Kent

Augt 16th

Dear Sir

I have this day received the microscopical specimens which you have been so kind as to forward to me.— I beg that you will be so good as to present my sincere thanks to the illustrious Ehrenberg,3 on your return to Berlin,4 for his present & I beg to remain | Dear Sir | Yours truly obliged | Ch. Darwin


The conjectured recipient is identified on the basis that CD had formerly sent samples of microscopic material to Christian Gottfried Ehrenberg via Bunsen, who was Prussian ambassador in London, 1841–54. See Correspondence vol. 3, letters to C. G. Ehrenberg, 21 May [1845], 29 October [1845], and letter to J. D. Hooker, [29 March or 5 April 1846].
The year is based on the watermark ‘Towgood 1853’ and the Down Bromley Kent address, which was used for only a brief period (July–December) in 1853. CD began to use it regularly in 1856, but the stationery of that year consistently has a Towgood 1855 watermark. See also n. 4, below.
Christian Gottfried Ehrenberg had corresponded with CD during the years 1844–6 when CD was writing South America (see Correspondence vol. 3). His microscopical analysis of Pampas mud and other specimens collected by CD helped to identify the nature of the geological deposits. In March 1853 Ehrenberg read two papers at the Akademie der Wissenschaften zu Berlin on the microscopical organisms he had found in CD’s Galápagos volcanic rock and mud specimens (Ehrenberg 1853a, pp. 178–9, and 1853b, pp. 180–94).
Bunsen was officially recalled to Berlin in April 1854 and left England in July of that year in order to spend the summer months at his home in Charlottenberg, near Bonn (Bunsen ed. 1868, 1: 330, 355).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

South America: Geological observations on South America. Being the third part of the geology of the voyage of the Beagle, under the command of Capt. FitzRoy RN, during the years 1832 to 1836. By Charles Darwin. London: Smith, Elder & Co. 1846.


Thanks correspondent for forwarding microscopical specimens, a present from C. G. Ehrenberg.

Letter details

Letter no.
Charles Robert Darwin
Christian Karl Josias Bunsen, Freiherr von Bunsen
Sent from
Source of text
The Morgan Library and Museum, New York (Heineman Collection MA 6511)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 902,” accessed on 27 October 2021,

Also published in The Correspondence of Charles Darwin, vol. 5