Inter machinas et organa id videtur esse discrimen, quod machinae pluribus operis ut vi maiore coguntur effectus habenti, uti ballistae torculariorumque prela; organa autem unius operae prudenti tactu perficiunt quod est propositum, uti scorpionis seu anisocyclorum versationes.
There seems to be this difference between machines and instruments, that machines are driven by several workmen as by a greater force producing its effects, for example, projectile engines or wine presses. But instruments carry out their purpose by the careful handling of a single workman, such as the turning of a hand balista or of screws.
final_alignments\Vitruvius_Architecture_Book_10.json