[8] It may be here mentioned that, as is well known to chemists, the efflorescences which often go by the name of “wall-saltpetre,” in most cases do not contain any saltpetre, but consist of sodium sulphate.
[9] Crum Brown, “Chem. Centralblatt,” 1890, I. p. 212; E. Simon, “Ueber Rostbildung u. Eisenanstriche,” p. 4.
[10] J. Spennrath, “Verhandlungen d. Vereins zur Beförd. d. Gewerbefleisses,” 1895, p. 245.
[11] “Christiania Videnskabs-Selskabs Forhandlinger” for 1892, No. 16, p. 8.
[12] “Chemische Zeitung. Repetitorium,” 1895, p. 289.
[13] “Chem. Centralblatt,” 1895, I. p. 441.
[14] Id., 1891, I. p. 860.
[15] “Berg- und Hüttenmännische Zeitung,” 1882, p. 469.
[16] [It may not be out of place here to give the main conclusions, drawn from a long series of experiments by Prof. W. R. Dunstan (“Proc. Chem. Soc.,” XIX. 150, 1903).
(a) Pure iron is not oxidised in the presence of gases and water-vapour only, but for the appearance of rust the presence of water in the liquid state is necessary.