Propriety is that perfection of style which comes when a work is authoritatively constructed on approved principles. It arises from prescription, from usage, or from nature.

But as for me, Emperor, nature has not given me stature, age has marred my face, and my strength is impaired by ill health. Therefore, since these advantages fail me, I shall win your approval, as I hope, by the help of my knowledge and my writings.

Next I must tell about the machine of Ctesibius, which raises water to a height.

Architect's designs must refer to the unquestionable perfection of the body's symmetry and proportions. If a building is to create a sense of eurythmia, it is essential that it mirrors these natural laws of harmony and beauty

All machinery is derived from nature, and is founded on the teaching and instruction of the revolution of the firmament.

There are also half bricks. As the bricks are always laid so as to break joints, this lends strength and a not unattractive appearance to both sides of such walls.

The construction of temples of the Ionic order to Juno, Diana, Father Bacchus, and the other gods of that kind, will be in keeping with the middle position which they hold; for the building of such will be an appropriate combination of the severity of the Doric and the delicacy of the Corinthian.