BOOK X.

465

is nineteen feet distant, and both these walls are thirty-six feet long andfourteen feet high ; a transverse wall extends from the end of the front wall tothe end of the rear wall; then fifteen feet back a second transverse wallis built out from the front wall to the end of the middle wall. In that spacewhich is between those two transverse walls are set up the stamps, by meansof which the ores and the necessary ingredients for smelting are broken up.From the further end of the front wall, a third transverse wall leads to theother end of the middle wall, and from the same to the end of the rear wall.The space between the second and third transverse walls, and between therear and middle long walls, contains the cupellation furnace, in which lead

arises—the abstrich. This material contains most of the antimony and arsenical impurities.In the third stage the litharge comes over. At the end of this stage the silver brightens—“ blicken ”—due to insufficient litharge to cover the entire surface. Winkler gives the follow-ing average proportion of the various products from a charge of 100 centners :—

AbzugAbstrichHerdtpleiImpure lithargeLitharge

2 centners, containing 64% lead

5i 73%

,, ,, 60% ,,

18 „ „ 85% „

66 „ „ 89% „

Total .. .. 113 centners

He estimates the lead loss at from 8% to 15%, and gives the average silver contents ofblicksilber as about 90%. Many analyses of the various products may be found in Percy(Metallurgy of Lead, pp. 198-201), Schnabel and Lewis (Metallurgy, Vol. 1, p. 581); but asthey must vary with every charge, a repetition of them here is of little purpose.

Historical Note on Cupellation. The cupellation process is of great antiquity,and the separation of silver from lead in this manner very probably antedates the separation ofgold and silver. We can be certain that the process has been used continuously for at least2,300 years, and was only supplanted in part by Pattinson’s crystallization process in 1833,and further invaded by Parks’ zinc method in 1850, and during the last fifteen years furthersupplanted in some works by electrolytic methods. However, it yet survives as an importantprocess. It seems to us that there is no explanation possible of the recovery of the largeamounts of silver possessed from the earliest times, without assuming reduction of that metalwith lead, and this necessitates cupellation. If this be the case, then cupellation was practisedin 2500 b.c. The subject has been further discussed on p. 389. The first direct evidence of theprocess, however, is from the remains at Mt. Laurion (note 6, p. 27), where the period ofgreatest activity was at 500 B.c., and it was probably in use long before that time. Ofliterary evidences, there are the many metaphorical references to “ fining silver ” and “ sepa-rating dross” in the Bible, such as Job (xxvm, 1), Psalms (xii, 6, lxvi, 10), Proverbs (xvii, 3).The most certain, however, is Jeremiah (vi, 28-30) : “ They are all brass [s«c] and iron ; they“ are corrupters. The bellows are burned, the lead is consumed in the fire, the founder“ melteth in vain ; for the wicked are not plucked away. Reprobate silver shall men call“ them.” Jeremiah lived about 600 b.c. His contemporary Ezekiel (xxn, 18) alsomakes remark : “ All they are brass and tin and iron and lead in the midst of the furnace ;“ they are even the dross of the silver.” Among Greek authors Theognis (6th century b.c.)and Hippocrates (5th century b.c.) are often cited as mentioning the refining of gold with lead,but we do not believe their statements will stand this construction without strain. Aristotle(Problems xxiv, 9) makes the following remark, which has been construed not only ascupellation, but also as the refining of silver in “ tests.” " What is the reason that boiling“ water does not leap out of the vessel .... silver also does this when it is purified." Hence those whose office it is in the silversmiths’ shops to purify silver, derive gain by“ appropriation to themselves of the sweepings of silver which leap out of the melting-pot.”

The quotation of Diodorus Siculus from Agatharcides (2nd century B.c.) on goldrefining with lead and salt in Egypt we give in note 8, p. 279. The methods quoted by Strabo(63 B.c-24 a.d.) from Polybius (204-125 B.c.) for treating silver, which appear to involvecupellation, are given in note 8, p. 281. It is not, however, until the beginning of the Christianera that we get definite literary information, especially with regard to litharge, in Dioscorides andPliny. The former describes many substances under the terms scoria, molybdaena, scoria argyrosand lithargyros, which are all varieties of litharge. Under the latter term he says (v, 62) :“ One kind is produced from a lead sand (concentrates ?), which has been’heated in the furnaces‘‘ until completely fused; another (is made) out of silver; another from lead. The best is