For not all things are practicable on identical principles

As regards the efficacy of the art and the theories of it, I promise and expect that in these volumes I shall undoubtedly show myself of very considerable importance not only to builders but also to all scholars.

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

Bricks should be made in Spring or Autumn so that they may dry uniformly.

When the juices of trees have no means of escape, they clot and rot in them, making the trees hollow and good for nothing.

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

In accordance with the foregoing investigations on mathematical principles, let bronze vessels be made, proportionate to the size of the theatre, and let them be so fashioned that, when touched, they may produce with one another the notes of the fourth, the fifth, and so on up the double octave.