To Julian Jackson 23 May 
My dear Sir
I received from Down this morning the Paper on the R. Negro.—1 I see by your note that it was sent from your office, on the very day, on which I left home.— I have given the best opinion I could on the Paper.— It appears to me pleasantly written, but most of the information might be found, scattered in other pub-lications. I found it impossible to mark out whole passages, as you requested.
Pray believe me | Yours very truly | C. Darwin Colonel Jackson
Discusses a paper on the Rio Negro.
Please cite as
Darwin Correspondence Project, “Letter no. 751,” accessed on 25 September 2016, http://www.darwinproject.ac.uk/DCP-LETT-751