One of the springs, called Aqua Argentina, deserves special attention; it comes out of the rock in a considerable body, and with much force, under the north-west corner of the Palatine Hill, at a great depth, in the cave called the Lupercal, which from its situation may very well have been a wolf’s cave at the time of the foundation of Rome. (702* is the plan and section of this). It falls into the larger stream that comes from the Quirinal and Capitoline Hills, and now runs in the Cloaca Maxima (690*). The point of junction of these two streams can be seen in an opening where the vault has been destroyed (158), near the arch of Janus and the church of S. Georgio in Velabro, which was the silversmiths’ quarter in Rome, as is shewn by the arch they erected in honour of Septimius Severus near this spot, the inscription on which remains. The stream that comes from the foot of the Quirinal, and now runs through the Cloaca Maxima, emerges in a cellar under a house at the back of the church of S. Hadrian, and a great body of water rises with considerable force. Such a spring is no doubt in its original place. Another spring that runs into this stream is the one that rises in the crypt under the church of the Crucifixion, at the foot of the Capitoline Hill, called the Prison of S. Peter, which is another natural source. Of the wells or reservoirs of rain-water, we have one remarkable example still preserved; it is on the Palatine Hill, at the north-west corner, just behind the most perfect part of the Wall of Romulus, and at one corner of his _arx_ or citadel, called Roma Quadrata, and there are certain peculiarities about it. It has _specus_, or subterranean conduits, to carry water to it from different parts of the hill. The cistern itself is seven feet high, of about the same width, and of considerable length. Into this reservoir descend certain wells of a peculiar and unusual form, like a hollow cone with the wide mouth downwards. This form of well is said to be common in the east; but the only examples known in this part of Italy are this one on the Palatine under the _arx_ of Romulus, and one at Alba Longa, under the corner of the _arx_ or citadel of that ancient city, from which the Romans are said to have been originally a colony. This is certainly a remarkable coincidence, if it is nothing more. One of these wells is shewn in 764 and 765 from nature, and in 366*, 384*, from a drawing. 1630 is a view of the reservoir at Alba Longa (mis-called the Prison). 1940* is from a drawing of the two compared. The remains of the aqueduct and reservoir at Tusculum (shewn in 1903) are of _opus quadratum_, of very early character, and seem to shew that the inhabitants there had aqueducts before the Romans. Frontinus, indeed, makes no claim to invention, nor were the Romans generally inventors, they rather turned to useful account the inventions of other people whom they had conquered.