Taylor - Theoretic Arithmetic.pdf - Platonic Philosophy

Nothing however which can be dissolved is incomposite, but is
by every necessity a composite.
CHAPTER XI.
On that number which is of itself second and composite, but
with reference to another first and incomposite.
THESE numbers therefore, i.e. the first and incomposite and
the second and composite being separated from each other by
a natural diversity, another number presents itself to the view
in the middle of these, which is indeed itself composite and
second, receives the measure of another, and is therefore capable
of a part with a foreign appellation, but when it is compared
with another number of the same kind, is conjoined with it
by no common measure; nor will these numbers have equivocal
parts. Numbers of this description, are such as 9 and 25;
for these have no common measure, except unity, which is the
common measure of all numbers. They likewise have no equivocal
parts. For that which in 9 is the third part is not in 25,
and that which in 25 is the fifth part is not in 9. Hence both
these numbers are naturally second and composite, but when
compared with each other, they arc rendered first and incomposite,
because each has no other measure than unity, which is
denominated from each; for in 9 it is the ninth, and in 25, the
twenty-fifth part.
CHAPTER XII.
On the generation of the first and incomposite, of the second
and composite numbers, and of that number which is of itself
second and composite, but with reference to another first and
rncom posite.