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Darwin Correspondence Project

From W. de W. Abney to Leonard Darwin   [before 27 June 1874]1

Per-centage composition of Carbonate of Ammonia as sold purified etc:

Gaseous Ammonia =(NH3) = 28.81
Carbonic Acid Gas (carbonic anhydride)= CO2 = 55.93
Water (of constitution) = H2O = 15.26
Propn of Nitrogen = 23.424

Nitrate of Ammonia (NH4NO3) (at 250o C) NH4NO3=2H2O (Water) + N2) (Nitrous Oxide) ∴ the salt really contains no water of crystallization, although a crystalline salt

Proportion of Nitrogen=35pr cent

Ordinary tribasic phosphate of ammonia (2NH4HPO4) + 4H2O contains.

Water (of cryst:) 35.33 p.c.
Nitrogen 13.425 "

In the anhydrous condition

Water nil
Nitrogen 21.21 p.c.2

CD annotations

Bottom of letter: ‘Mr W W Abney | [LNE]


The date is established by the relationship between this letter and the letter from Leonard Darwin to W. de W. Abney, [before 27 June 1874]
CD used the figures for the amount of nitrogen in these compounds in Insectivorous plants (see letter from Leonard Darwin to W. de W. Abney, [before 27 June 1874] and n. 2).


Insectivorous plants. By Charles Darwin. London: John Murray. 1875.


Answers questions about chemistry (see 9202).

Letter details

Letter no.
William de Wiveleslie Abney
Leonard Darwin
Source of text
DAR 58.1: 148

Please cite as

Darwin Correspondence Project, “Letter no. 9196F,” accessed on 22 January 2021,

Also published in The Correspondence of Charles Darwin, vol. 22