Note 45 — PART I. THE CHANGES UNDERGONE BY ANTIQUITIES IN EARTH AND IN AIR.

[Several other analyses of bronzes from various sources have been recently published. Thus Natterer (“Monatshefte für Chemie,” XXI. 256, 1900; also “Chem. Centralblatt,” 1900, I. 1262) examined a corroded bronze statuette from Ephesus. The bronze contained:—Tin 6·09%, lead 4·87%, and copper 89·64%, with traces of zinc.

Bassett (“Proc. Chem. Soc.,” 1903, XIX. 95) gives an analysis of the base of an Egyptian statuette, found in the Nile Delta, probably dating from 200-100 B.C. The base was hollow but filled with lead, and was covered with a thick green coating, which in parts entirely replaced the original metal.

Table I.

Cu 50·65%

Pb 6·74%

Sn 2·94%

Fe 0·15%

Ni, Mn, etc. 0·11%

Cl 15·71%

SiO₂ (as sand) 1·14%

H₂O 11·07%

(NH₄) 0·11%

88·62%

Table II.

CuCl₂ 29·34%

CuO 46·10%

H₂O 11·07%

SnO₂ 3·73%

PbO 7·26%

Fe₂O₃ 0·22%

NiO, etc. 0·14%

SiO₂ 1·14%

(NH₄)Cl 0·32%

99·32%

In the second column the chlorine has been calculated as copper chloride, the remaining copper and other metals as oxides.

Traces of calcium were also found, but the amount of sodium was so small that it could only be detected by the flame test. If all the copper had been present as basic chloride (atacamite CuCl₂, 3CuO, 3H₂O), this would require 26·84% CuCl₂, 47·57% CuO, and 10·78% H₂O. It would therefore appear that the substance produced by corrosion is less basic than atacamite, and that ammonium chloride may have played a more important part than sodium chloride in the formation of copper chloride, for in this case the sodium was only found in amount too small for estimation.

An analysis of the earliest piece of bronze known, i.e. that from Mêdûm, Egypt (3700 B.C.), gives 8·4% of tin (inner core 9·1%) to 89·8 of copper with a small quantity of arsenic.

An analysis of a celt from the Dowris find (King’s County, Ireland, 1825) gave copper, 85·23; tin 13·11; lead 1·14, with traces of sulphur and carbon. The waste material from the same place yielded 89% copper, 11% tin, with traces only of lead, iron and silver.

On the other hand an early bronze celt (Butterwick, E.R., Yorks.) showed a smaller quantity of tin—10·74%, compared with 87·97% of copper. (Guide to Bronze Age Antiquities, British Museum.)

Mr George Coffey has also published (“Brit. Assoc. Reports,” 1899, p. 873) a tabulated series of analyses of Irish celts which proved to be composed of practically pure copper. Transl.]