We have proof of two methods of calculation in ancient Rome, one by the
first method, in which the surface of sand was divided into columns by a
stylus or the hand. Counters (_calculi_, or _lapilli_), which were kept
in boxes (_loculi_), were used in calculation, as we learn from Horace’s
schoolboys (Sat. 1. vi. 74). For the sand see Persius I. 131, “Nec qui
abaco numeros et secto in pulvere metas scit risisse,” Apul. Apolog. 16
(pulvisculo), Mart. Capella, lib. vii. 3, 4, etc. Cicero says of an
expert calculator “eruditum attigisse pulverem,” (de nat. Deorum,
ii. 18). Tertullian calls a teacher of arithmetic “primus numerorum
arenarius” (de Pallio, _in fine_). The counters were made of various
materials, ivory principally, “Adeo nulla uncia nobis est eboris, etc.”
(Juv. XI. 131), sometimes of precious metals, “Pro calculis albis et
nigris aureos argenteosque habebat denarios” (Pet. Arb. Satyricon, 33).
There are, however, still in existence four Roman counting boards of a
kind which does not appear to come into literature. A typical one is of
the third class. It consists of a number of transverse wires, broken at
the middle. On the left hand portion four beads are strung, on the right
one (or two). The left hand beads signify units, the right hand one five
units. Thus any number up to nine can be represented. This instrument is
in all essentials the same as the Swanpan or Abacus in use throughout
the Far East. The Russian stchota in use throughout Eastern Europe is
simpler still. The method of using this system is exactly the same as
that of _Accomptynge by Counters_, the right-hand five bead replacing
the counter between the lines.