Note 57 — Chapter IV · PART I. THE AQUEDUCTS.
Reading edition
The gemelli are, in all probability, the large twin reservoirs just outside the western wall of the Sessorium, now in a large vineyard near the Porta Maggiore, through which the Neronian arches pass. These reservoirs are below the level of the specus of the Anio Vetus, as was shewn by some excavations made in them under my direction in 1869.