M. Vitruvius per Iocundum solito castigatior factus cum figuris et tabula ut iam legi et intelligi possit

A decorative initial letter 'E' begins the text.

Eurythmy is a graceful appearance and a comfortable aspect in the composition of parts. This is achieved when the parts of the work are convenient—the height to the width, the width to the length—and all things respond to their symmetry in the final result. Symmetry is likewise a convenient response from the members of the work itself, and from the separate parts to the appearance of the entire figure, a proportion of the part: as in the human body, the cubit, foot, palm, finger, and other parts are symmetrical, so it is in the perfection of works. And first in sacred buildings, the reasoning of symmetries is found from the thickness of the columns, or from the triglyph, or even from the opening of a ballista, which the Greeks call peritretos bored through, or in ships from the inter-scalmium space between rowing benches, which is called diapeche two-cubit span, and likewise from the members of other works. Decor, however, is the polished aspect of a work, composed of approved things with authority. It is perfected by station, which in Greek is called thematismos theme/placement, or by custom, or by nature. Station is when buildings are constructed for Jupiter, for lightning, and for the heavens and the moon, in the open air and without roofs hypaethral. For we see the species and effects of these gods present in the open and shining world. For Minerva, Mars, and Hercules, Doric temples shall be made. For it is fitting that buildings be constructed for these gods without delicacy, on account of their virtue. For Venus, Flora, Proserpina, and the nymphs of the springs, built in the Corinthian style, they will appear to have appropriate properties: because for these gods, on account of their tenderness, more slender and floral works, adorned with leaves and volutes, will appear to augment the just decor. For Juno, Diana, Father Liber Bacchus, and other gods who are of the same similarity, if Ionic temples are constructed, a ratio of moderation will be held: because their institution of propriety will be tempered from the severe manner of the Doric and from the tenderness of the Corinthian. Decor is expressed by custom when, with magnificent interior buildings, corresponding vestibules of elegance are also made. For if the interiors have elegant finishes but the entrances are humble and dishonest, they will not be with decor. Likewise, if dentils are carved into the cornices of Doric architraves, or if triglyphs are expressed in pulvinated capitals and Ionic architraves, the properties being transferred from another system into a different genus of work, the aspect will be offended, as other customs of order were previously established. Natural decor will be thus: if first, for all temples, the most salubrious regions and suitable springs of water are chosen in those places where shrines are to be established; then especially for Aesculapius and Salus Goddess of health, and of those gods by whose medicines the sick appear to be cured in large numbers. For when sick bodies are moved from a pestilent to a salubrious place, and the use of water is supplied from salubrious springs, they will recover more quickly. Thus, it will be brought about that from the nature of the place, the divinity receives greater and more dignified opinions.