If our designs for private houses are to be correct, we must at the outset take note of the countries and climates in which they are built.

At Jaffa in Syria and among the Nomads in Arabia, are lakes of enormous size that yield very large masses of asphalt, which are carried off by the inhabitants thereabouts.

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.

The proper form of economy must be observed in building houses for each and every class.

Fresh pitsand, however, in spite of all its excellence in concrete structures, is not equally useful in stucco, the richness of which, when the lime and straw are mixed with such sand, will cause it to crack as it dries on account of the great strength of the mixture. But river sand, though useless in "signinum" on account of its thinness, becomes perfectly solid in stucco when thoroughly worked by means of polishing instruments.

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.