I
116
PYTHAGOREAN ARITHMETIC
that is, what we call a digit of a number expressed in our
decimal notation ; for the Greeks, in the case of any number
above 9, the pythmen was the same number of units as the
alphabetical numeral contains tens, hundreds, thousands, &c.
Thus the pythmen of 700 (\fr in Greek) is 7 (£); that of
(6000) is <y (6), and so on. The method then proceeded
to find the pythmen of a certain name, say Ayayeyvcov.
Taking the pythmenes of all the letters and adding them,
we have
1 + 34-1+4 + 5 + 4 + 5 + 8 + 5 = 36.
Take the pythmenes of 36, namely 3 and 6, and their sum is
9. The pythmen of Ayayeyrcov is therefore 9. Next take
the name "Ektcop; the pythmenes are 5, 2, 3, 8, 1, the sum of
which is 19 ; the 'pythmenes of 19 are 1, 9 ; the sum of 1 and
9 is 10, the pythmen of which is 1. The pythmen of "Ektcop
is therefore f, ‘ It is easier ’, says Hippolytus, ‘ to proceed
thus. Finding the pythmenes of the letters, we obtain, in the
case of "Ektcop, 19 as their sum. Divide this by 9 and note
the remainder: thus, if I divide 19 by 9, the remainder is 1,
for nine times 2 is 18, and 1 is left, which will accordingly
be the pythmen of the name "Ektcop.’ Again, take the name
TldrpoKXos. The sum of the pythmenes is
8 + l + 3 + l + 7 + 2 + 3+ ^ + 2 = 34 ;
and 3 + 4 = 7, so that 7 is the pythmen of Udrpo/cXoy.
‘ Those then who calculate by the rule of nine take one-ninth
of the sum of the pythmenes and then determine the sum of
the pyythmenes in the remainder. Those on the other hand
who follow the “ rule of seven ” divide by 7. Thus the sum
of the pythmenes in Harpo/cXcy was found to be 34. This,
divided by 7, gives 4, and since 7 times 4 is 28, the remainder
is 6. . . .’ ‘ It is necessary to observe that, if the division
gives an integral quotient (without remainder), . . . the
pythmen is the number 9 itself ’ (that is, if the rule of nine is
followed). And so on.
Two things emerge from this fragment. (1) The use of the
pythmen was not appearing for the first time when Apollonius
framed his system for expressing and multiplying large
numbers; it originated much earlier, with the Pythagoreans.