While all bodies are composed of the four elements, that is, of heat, moisture, the earthy, and air, yet there are mixtures according to natural temperament which make up the natures of all the different animals of the world, each after its kind.

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...

In order that the mortar in the joints may not suffer from frosts, drench it with oil-dregs every year before winter begins. Thus treated, it will not let the hoarfrost enter it.

In fact, all kinds of men, and not merely architects, can recognize a good piece of work.

For we must not build temples according to the same rules to all gods alike, since the performance of the sacred rites varies with the various gods.

Oak... lasts for an unlimited period when buried in underground structures... when exposed to moisture... it cannot take in liquid on account of its compactness, but, withdrawing from the moisture, it resists it and warps, thus making cracks.

The thickness of the walls should be sufficient for two armed men to pass each other with ease.