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Lesson
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 are 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.
Assessment
