‹‹‹ Vitr. 10.1.2 | Table of Contents | Vitr. 10.1.4 ›››
3Of these some act mechanically, others organically. The difference between machines and organs is this, that the former are composed of many subordinate parts, or propelled by a great power, as balistæ for instance, and wine-presses; whereas, the latter, by an ingenious application of the moving power, can be set in motion by a single person, as in turning the axis of the scorpion or anisocycli. Thus organs, as well as machines, are extremely useful and necessary, inasmuch as, without them, no works could be carried into execution.
3Some of these act on the principle of the μηχανἡ, others on that of the ὁργανον. The difference between “machines” and “engines” is obviously this, that machines need more workmen and greater power to make them take effect, as for instance ballistae and the beams of presses. Engines, on the other hand, accomplish their purpose at the intelligent touch of a single workman, as the scorpio or anisocycli when they are turned. Therefore engines, as well as machines, are, in principle, practical necessities, without which nothing can be unattended with difficulties.