[131] “Chemiker Zeitung,” XI. 1887, p. 605.
[132] Ant. Fr. 1154 a.
[133] I should now use paraffin for impregnation. (Author’s note.)
[134] [Great caution must be used to prevent inhalation of the gas, which is extremely poisonous. Transl.]
[135] Instead of potassium cyanide, I have made experimental use of the much more readily fusible potassium sulphocyanide. This converts the iron compounds into iron sulphide, which is easily got rid of. The sulphide which still adheres to the iron and imparts a not unpleasing blackish colour to the object appears to be stable.
The rest of the treatment is similar to that above described. Having so far only experimented with a few specimens I am not yet in a position to offer any judgment as to the practicability of the process. (Author, 1904.) [For practical objections to this method, which we do not consider satisfactory owing to the instability of the products resulting from the reaction, and the difficulty in removing them by the subsequent washing, see Milbauer, “Zeit. f. anorg. Chem.” XLII. 1904, p. 433 (“Journ. Chem. Soc.” Abstracts, i. 121), where it is stated that treatment of Fe2O3 at 400°C. leads to the formation of K2Fe2S4. Transl.]
[136] Stolba, “Chemiker Zeitung,” XX. 1896, Repertorium, p. 240. [Sodium sulphide has a very deleterious action upon the skin and fingernails which should be protected when using this substance. Transl.]
[137] Flinders Petrie, “Archaeological Journal,” Vol. XLV. 1888, p. 88.
[138] Cp. Mugdan, “Zeit. Elektrochem.” 1903, ix. p. 442.
[139] [A method used by the explorers of the Palestine Exploration Committee for the preservation of much decayed bronzes, as, for instance, those from wells and cisterns, is to place them immediately they are discovered into a strong solution (1 in 10) of carbolic acid. Transl.]