Frontinus. The number of open reservoirs was afterward increased. Heavy penalties were inflicted for dipping a dirty vessel into one of these reservoirs. Of the total supply, a little over one-third was given to the public, and the remainder divided pretty evenly between private and imperial purposes. The wealthy had water brought into reservoirs within the courts of their residences, whence it was raised to the upper stories in buckets worked by windlasses. This method of supplying the upper stories is in use at the present time. The Romans had no pumps. Why the water was not conveyed upward in pipes does not appear, except that in regard to the more elevated parts of the city it was probably not brought in at a high enough level. They possessed lead pipes of different sizes, and stopcocks of bronze and silver, for these have been found in various places; and that they were perfectly familiar with the principle of hydraulics, that water may be returned to its original level, is proved not only by the construction of the filtering-places already described, but also by the fact that they actually applied the principle on a stupendous scale. Besides, there is a work of Vitruvius extant which recognizes and gives directions for conveying water on this principle. An aqueduct constructed by the Emperor Claudius, for the ancient city of Lugdunum (now Lyons), possessed two inverted siphons, by which the water was carried across deep valleys. There is no doubt that they were acquainted, too, with the poisonous action of lead on water; but, if that deterred them from raising the water, it shows they were more careful in guarding against unhealthful influences than we moderns are, for lead pipes are in general use to distribute water through our houses to-day.
The aqueducts were placed under the care of a curator aquarum, and afterward, in the time of Diocletian, under several magistrates, called consulares aquarum. The actual attendants numbered 700, and were divided into the familia publica and the familia Cæsaris. The former, 240 in number, were paid by the state; the latter, 460, by the emperor. With regard to the cost of building the aqueducts, it seems to have been defrayed, in the majority of cases, out of government funds; but it is recorded in an inscription on the Porta Maggiore, a gate of the city over which the conduits of the Claudia and Anio Nevus were carried, that those two aqueducts were built by the Emperor Claudius at his own expense. This gate affords a clew to the reason why arcades instead of solid walls were used to carry the aqueducts across the plains: it was not solely for economy's sake, nor for beauty's; but while those considerations, no doubt, were entertained, the main object was, to avoid interference with the freedom of travel.
The aqueducts were all destroyed in the Gothic wars under Vitiges and Totila, but the most important of them were restored either by Belisarius or Narses. These, however, fell gradually into decay, and ultimately became useless. Pope Paul III. (1540) restored to use the