He estimates the lead loss at from 8% to 15%, and gives the average silver contents of
blicksilber 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 as
they 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 of
gold and silver. We can be certain that the process has been used continuously for at least
2,300 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 further
supplanted in some works by electrolytic methods. However, it yet survives as an important
process. It seems to us that there is no explanation possible of the recovery of the large
amounts of silver possessed from the earliest times, without assuming reduction of that metal
with lead, and this necessitates cupellation. If this be the case, then cupellation was practised
in 2500 b.c. The subject has been further discussed on p. 389. The first direct evidence of the
process, however, is from the remains at Mt. Laurion (note 6, p. 27), where the period of
greatest activity was at 500 b.c., and it was probably in use long before that time. Of
literary evidences, there are the many metaphorical references to " fining silver " and " separating dross" in the Bible, such as Job (xxvm, 1), Psalms (xn, 6, lxvi, 10), Proverbs (xvn, 3).
The most certain, however, is Jeremiah (vi, 28-30) : " They are all brass [sic] 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) also
makes 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 as
cupellation, 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 gold
refining 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 involve
cupellation, are given in note 8, p. 281. It is not, however, until the beginning of the Christian
era that we get definite literary information, especially with regard to litharge, in Dioscorides and
Pliny. The former describes many substances under the terms scoria, molybdaena, scoria argyros
and 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
