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Darwin Correspondence Project

From C. H. Blackley   7 July 1873

Arnside House, | Stretford Road, | Manchester.

July 7th 1873

Dear Sir,

My best thanks to you for the copy of Dr Wyman’s book you have been kind enough to send me.1 I shall prize it very much because it comes from you. I saw the advertisement of it, for the first time, a couple of weeks or so after my own book2 was published and at once asked my bookseller to send for a copy. This I have had by me about a month, and after having carefully read it am very much pleased with it. I regret that I did not know of the book before the later chapters in my own were written as I think many of the facts Dr Wyman gives would have helped to strengthen my position.

Now that I have the copy you have been kind enough to send me I shall send my own to Dr Phœbus, of Giessen, who I think must not have seen the work or he would have named it in a letter I had from him a few weeks ago.3

It may perhaps interest you to know that it is to your observations on the distances to which dust may be carried by atmospheric currents that my experiments at high altitudes are mainly owing. I had long had the idea that such experiments might reveal something curious; but it was only after reading your Narrative of the Voyage of the Beagle (which I did in 1864) that the idea fairly took, and kept, possession of me until I had worked it out in the way you will find described.4 If, after reading my book, you have, amidst your many engagements, time to pen a line and tell me what you think of the results of the experiments at high altitudes I shall be glad to have a line;5 but do not let me trespass too much on your valuable time because I do not forget that I am an entire stranger to you.

Again thanking you for your kindness. | I Remain Dear Sir | Yours Very Truly | Chas H Blackley

Chas Darwin Esq M.A. F.R.S. &c


Blackley refers to Morrill Wyman’s book Autumnal catarrh (M. Wyman 1872).
Experimental researches on the causes and nature of catarrhus aestivus (Blackley 1873).
Philipp Phoebus wrote a study of hay fever (Phoebus 1862).
CD had discussed collecting atmospheric dust at Porto Praya in Journal of researches 2d ed., p. 5. Blackley was sampling air at high altitudes to determine whether pollen could be carried long distances by the wind. He concluded that in pollen seasons much more pollen was found between 1000 and 2000 feet above ground than at ground level, and this explained why people suffered from hay fever in large cities far away from sources of pollen (Blackley 1873, pp. 115–53; see also Taylor and Walker 1973, p. 106).
Evidently Blackley had not yet received CD’s letter of 5 July [1873].


Blackley, Charles Harrison. 1873. Experimental researches on the causes and nature of catarrhus æstivus (hay-fever or hay-asthma). London: Bailliere, Tindall & Cox.

Journal of researches 2d ed.: Journal of researches into the natural history and geology of the countries visited during the voyage of HMS Beagle round the world, under the command of Capt. FitzRoy RN. 2d edition, corrected, with additions. By Charles Darwin. London: John Murray. 1845.

Wyman, Morrill. 1872. Autumnal catarrh (hay fever). New York: Hurd and Houghton.


Thanks for copy of Wyman’s book.

His own recent researches [on pollen] at high altitudes were inspired by CD’s account in Journal of researches of distances dust may travel.

Letter details

Letter no.
Charles Harrison Blackley
Charles Robert Darwin
Sent from
Source of text
DAR 160: 192
Physical description
ALS 3pp

Please cite as

Darwin Correspondence Project, “Letter no. 8967,” accessed on 19 September 2023,

Also published in The Correspondence of Charles Darwin, vol. 21