Note 401 — Chapter XI · THE COPPER AND SILVER GROUPS. PRECIPITATION WITH HYDROGEN SULPHIDE

The calculation was made by the method used by Knox (loc. cit.) for a molar solution. The degree of ionization of the salt was not considered and the correct ionization constant for ammonium hydroxide was used, 1.8E−5 in place of 2.3E−5. The latter, evidently, was used by Knox as the result of overlooking a correction, which Bredig made in his (Bredig's) first calculations of the constant; cf. Bredig, Z. phys. Chem., 13, 293, footnote. The same erroneous constant is found in Kohlrausch and Holborn, loc. cit., p. 194.