bring into the city, I will give you the calculation made in 1857 by Signor Cavalieri di San Bertolo, long engineer to the water supply of Rome.[1]
Any one who has visited the Eternal City must have seen the great market-place, called Piazza Navona, on one side of which, occupying one-half of it, stand the great Pamphily palace, and the elegant church of St. Agnes. Now suppose that immense area to be enclosed, so as to become a reservoir, the walls of which shall rise to the roof of the palace; that reservoir would exactly contain the quantity of water that enters Rome every twenty-four hours.
Or, to reduce this fact to figures, it will be as follows, omitting fractions.
The area of the Piazza made quadrangular is 813 English feet by 170, or 66,586 square feet, which, raised to the height of about 66 feet, the elevation of the Palace, gives 4,282,507 cubic feet, or, if filled with water, 2,224,274 gallons of water.
This is the daily supply of modern Rome, brought by three aqueducts. It is at the rate of 321 gallons per day for every inhabitant.[2]
Now, keep in mind that this is the water furnished by three aqueducts; whereas ancient Rome was supplied by nineteen or twenty. There exists a Roman author (Frontinus) who has given us an account of their supplies, in measures tolerably explicable.
The result is, that calculating the number of in-
