10The Apennines begin from the Tyrrhene Sea, extending to the Alps on one side, and the borders of Tuscany on the other; and their summits spreading in the shape of a bow, almost touch the shores of the Adriatic in the centre of their range, which ends near the Straits of Sicily. The hither side of them towards Tuscany and Campania, is in point of climate extremely mild, being continually warmed by the sun’s rays. The further side, which lies towards the upper sea, is exposed to the north, and is enclosed by thick and gloomy shadow. The trees, therefore, which grow in that part being nourished by continual moisture, not only grow to a great size, but their fibres being too much saturated with it, swell out considerably. When hewn, therefore, and squared, and deprived of their natural vegetation, they change in drying the hardness of the grain, and become weak and apt to decay, on account of the openness of their pores. They are, therefore, of little durability in buildings.
2On the contrary, those which grow on the side opposite to the sun, not being so porous, harden in drying, because the sun draws the moisture from trees no less than from the earth. Hence, those which grow in open sunny places, are more solid, on account of the closeness of their pores, and when squared for use, are exceedingly lasting. The fir, which goes by the name of Infernas, brought from the warm open parts, is therefore preferable to the sort called Supernas, which comes from a closely and thickly wooded country.
3To the best of my ability I have treated on the materials necessary for building, and their natural temperaments in respect of the different proportions of the elements which they contain, as well as on their good and bad qualities, in order that those who build may be well informed thereon. Those who follow my directions, and choose a proper material for the purpose whereto it is applied, will do right. Having thus considered the preparations to be made, we shall proceed, in the following books, to the consideration of buildings themselves, and first, to that of the temples of the immortal gods, and their symmetry and proportions as the importance of the subject requires, which will form the subject of the following book.