‹‹‹ Vitr. 8.6.11 | Table of Contents | Vitr. 8.6.13 ›››
12If there be no springs from which water can be obtained, it is necessary to dig wells, on which every care is to be bestowed, and the utmost ingenuity and discretion used in the examination of the natural indications of the circumstances thereabout, inasmuch as the different sorts of soil which are met with, are many and various. That, like every other body, is composed of four elements; first of earth itself; water, whence are the springs; heat, whence sulphur, alum, and bitumen are generated; and air, whence arise great vapours, which, piercing through the pores to the opening of wells, strike upon the excavators and suffocate them by their natural influence, so that those who do not immediately escape lose their lives.
12But if there are no springs from which we can construct aqueducts, it is necessary to dig wells. Now in the digging of wells we must not disdain reflection, but must devote much acuteness and skill to the consideration of the natural principles of things, because the earth contains many various substances in itself; for like everything else, it is composed of the four elements. In the first place, it is itself earthy, and of moisture it contains springs of water, also heat, which produces sulphur, alum, and asphalt; and finally, it contains great currents of air, which, coming up in a pregnant state through the porous fissures to the places where wells are being dug, and finding men engaged in digging there, stop up the breath of life in their nostrils by the natural strength of the exhalation. So those who do not quickly escape from the spot, are killed there.