She makes each separate thing for a separate end
And she does so because the instrument is most perfectly made when it serves a single purpose and not a variety of purposes.
Among barbarians, however, the female and the slave occopy the same position
The reason being that no naturally ruling element exists among them, and conjugal union thus comes to be a union of a female who is a slave with a male who is also a slave.
This is why our poets have said,
The female and the slave are naturally distinguished from one another: nature makes nothing in a miserly spirit, as smiths do when they make the Delphic knife to serve a number of purposes: