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Darwin Correspondence Project

From C. W. Hamilton   21 February 1879

40 Dominick st | Dublin

Feby 21. 1879


I almost feel that you will not consider me intrusive in asking you to look over this note—as far as I can find out nothing of this kind has been noticed before & what I have seen must either be otherwise explained or deemed a matter of Considerable importance—1 my accuracy can be very easily tested as there is nothing to do but to cut a twig, smear a glass slide as thinly as possible to spread the little bubbles of gum, & touch them with a solution of Sulphid Iron—which acting on the tannin brings out the forms to a certain degree in a few minutes but more perfectly after some hours. Since I sent this note to the press I think I have had abundant Confirmation of the fact that the arrangement of this substance of the so called Resin takes Vegetable forms   Take for instance this one from P. Douglassii2


where the plates of the hexagonal Chrystal like form seem to develop into the Common branch like form sketched then take this lying close by


When the side diagram forms open out into circular forms bending in different directions surely this is not Chrystallization?

Now again in the living P. Insignis3 I find curious forms in the centre of the Channel leading from the Pith to the outburst of branch or Leaf


and again in the Sap what I have drawn above— roughly from more accurate sketches—can it be that these forms are merely Chrystals though imitating so Closely the forms we meet in the growing plant?

With many apologies for venturing to Consult such a Philosopher believe me with great respect | Yours faithfully | Charles W Hamilton


Hamilton’s note is not in the Darwin Archive–CUL and has not been further identified. Sulphid iron: probably ferrous sulphate (FeSO4), which is soluble.
Pseudotsuga douglasii is a synonym of Pseudotsuga menziesii, the Douglas fir. The tree can exude resin or pitch after it is cut down. The images are reproduced at 80 per cent of their original size.
Pinus insignis is a synonym of Pinus radiata var. radiata (Monterey pine).


Encloses a press clipping [missing] of his observations [on stem structure?].

Letter details

Letter no.
Charles William Hamilton
Charles Robert Darwin
Sent from
Source of text
DAR 166: 91
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 11898,” accessed on 15 April 2024,