The mint of Rome.] [Footnote: See Pl. LXXVI. This passage is taken
from a note book which can be proved to have been used in Rome.]

All coins which do not have the rim complete, are not to be accepted
as good; and to secure the perfection of their rim it is requisite
that, in the first place, all the coins should be a perfect circle;
and to do this a coin must before all be made perfect in weight, and
size, and thickness. Therefore have several plates of metal made of
the same size and thickness, all drawn through the same gauge so as
to come out in strips. And out of [24] these strips you will stamp
the coins, quite round, as sieves are made for sorting chestnuts
[27]; and these coins can then be stamped in the way indicated
above; &c.

[31] The hollow of the die must be uniformly wider than the lower,
but imperceptibly [35].

This cuts the coins perfectly round and of the exact thickness, and
weight; and saves the man who cuts and weighs, and the man who makes
the coins round. Hence it passes only through the hands of the
gauger and of the stamper, and the coins are very superior.
[Footnote: See Pl. LXXVI No. 2. The text of lines 31-35 stands
parallel 1. 24-27.

Farther evidence of Leonardo's occupations and engagements at Rome
under Pope Leo X. may be gathered from some rough copies of letters
which will be found in this volume. Hitherto nothing has been known
of his work in Rome beyond some doubtful, and perhaps mythical,
statements in Vasari.]