Some make twenty-five needles, in order to be able to detect the two
scripula of silver or copper which are in a bes of gold. Of these needles, the
first is composed of twelve duellae of gold and six of silver, and the same
number of copper. The second, of twelve duellae and one sextula of gold, and
five duellae and one and a half sextulae of silver, and the same number of
duellae and one and a half sextulae of copper. The remaining needles are
made in the same proportion.
Pliny is our authority that the Romans could tell to within one scripulum
how much gold was in any given alloy, and how much silver or copper.
Needles may be made in either of two ways, namely, in the ways of which
I have spoken, and in the ways of which I am now about to speak. If
