John Henry Parker,
The archæology of Rome, Part VIII
(1876)
“ At about every half-mile the specus forms an angle to break the force of the water, and at such points there is usually a reservoir also. Advantage was taken of these angles for the later aqueducts to be carried over the older ones, as at the Torre Fiscale and the Porta Maggiore. These precautions, combined with the system of Piscinæ, rendered the water constantly fresh, pure, and wholesome.From some considerable remains of the Piscinæ, the system can be clearly made out. The building consisted of four chambers, two beneath and two above. ”
