let down from the pulley of the crane arm; the inside diameter of this ring
is six digits, and it is about a digit and a half thick ; the ring is then engaged
in the hook whose straight stem is in the cake, and thus the cake is raised from
the mould and put into its place.
The copper and lead, when thus melted, yield a small amount of " slag "ia
and much litharge. The litharge does not cohere, but falls to pieces like the
residues from malt from which beer is made. Pompholyx adheres to the walls
in white ashes, and to the sides of the furnace adheres spodos.
In this practical manner lead is alloyed with copper in which there is but
a moderate portion of silver. If, however, there is much silver in it, as, for
instance, two librae, or two librae and a bes, to the centumpondium,—which
weighs one hundred and thirty-three and a third librae, or one hundred and
forty-six librae and a bes,n—then the foreman of the works adds to a centumpondium of such copper three centumpondia of lead, in each centumpondium
of which there is a third of a libra of silver, or a third of a libra and a semiuncia. In this manner three liquation cakes are made, which contain
altogether three centumpondia of copper and nine centumpondia of lead.14 The
lead, when it has been liquated from the copper, weighs seven centumpondia;
and in each centumpondium—if the centumpondium of copper contain two
librae of silver, and the lead contain a third of a libra—there will be a libra
and a sixth and more than a semi-uncia of silver; while in the exhausted
liquation cakes, and in the liquation thorns, there remains a third of a libra.
"An analysis of this " slag " by Karsten (Archiv, ist Series IX, p. 24) showed 63.2%
lead oxide, 5.1% cuprous oxide, 20.1% silica (from the fuel and furnace linings), together
with some iron alumina, etc. The pompholyx and spodos were largely zinc oxide (see note,
P· 394)·
"This description of a centumpondium which weighed either 133J librae, or 146I librae,
adds confusion to an already much mixed subject (see Appendix C). Assuming the
German pfundt to weigh 7,219 troy grains, and the Roman libra 4,946 grains, then a centner
would weigh 145.95 librae, which checks up fairly well with the second case ; but under what
circumstances a centner can weigh 133 J librae we are unable to record. At first sight it might
appear from this statement that where Agricola uses the word centumpondium he means the
German centner. On the other hand, in the previous five or six pages the expressions one-third,
five-sixths, ten-twelfths of a libra are used, which are even divisions of the Roman 12 unciae
to one libra, and are used where they manifestly mean divisions of 12 units. If Agricola
had in mind the German scale, and were using the libra for a pfundt of 16 untzen, these divisions
would amount to fractions, and would not total the stctitcMs and drachma, quantities given,
nor would they total any of the possibly synonymous divisions of the German untzen (see
also page 254).
14If we assume Roman weights, the charge in the first case can be tabulated as follows,
and for convenience will be called the fifth charge :—
