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Darwin Correspondence Project

From Leonard Darwin   7 January 1878

Brompton Barracks, | Chatham.

Jan 7th. 1878

Dear Father

The following is the work on the lamp black so far. Boiled 25 grains in water; filtered; obtained a clear solution with a very slight green tint; evaporated to dryness and a residue was left; this may have been oil that came through with the hot water; then I red heated the residue, and a good deal went away with badly smelling fumes; there only remained .08 grain   I think that this contained a trace of iron; and that most of it was some soda salt, but I cannot be sure.1 The result in numbers is

Percentage of organic matter that came through with the water—– 1.92
Percentage of inorganic matter soluble in water.—– 0.32

Your affec son | L. Darwin.


CD wanted to know the composition of an ointment that he had applied to the shoots of plants; see letter to W. W. Baxter, 6 January [1878].


LD’s chemical analysis of lamp-black.

Letter details

Letter no.
Leonard Darwin
Charles Robert Darwin
Sent from
Brompton Barracks, Chatham
Source of text
DAR 209.8: 153
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11316,” accessed on 25 October 2021,