The fountain of the Piazza Colonna might be the “Fountain of Youth,” for the freshness of its marbles makes it seem to date from yesterday, whereas it is in reality one of the oldest fountains of modern Rome. It was constructed three hundred and twenty-five years ago, and belongs to that period when the Acqua Vergine (Trevi Water) was the only water with which to feed a fountain. As the Acqua Vergine has not sufficient head to rise to any great height, and as its supply is in continuous and wide-spread use for domestic purposes, the designs for the fountains which it furnishes have to be low, and the sculptor or architect must rely for his effect not upon any lavish supply of water but upon the beauty of his materials and his own imagination. The fountains of Giacomo della Porta show the practical difficulties with which he had to contend, and the felicity of his genius in overcoming the limitation. His fountain of the “Tartarughe” is a work of art, and as such can be admired without the aid of the water. The two side fountains in the Piazza Navona, also his creations, were quite lovely before Bernini decorated one and artists of the nineteenth century the other with fantastic sculpture. His fountain of the Piazza Colonna has been less tampered with and, standing in full sunlight or darkened by the vast shadow of the Antonine Column, it remains, in its quiet beauty, a masterpiece among the Roman fountains. It is a graceful, hectagonal receptacle, half basin, half drinking-trough, composed of different kinds of Porta Santa marble. These are joined together with straps of Carrara ornamented by lions’ heads.[G] Its waters come to it from a vase of antique shape standing in the centre. From the shallow bowl of this central vase the water gushes upward to fall over the rim in a soft, unbroken, silvery stream, and through this vestal’s veil the Carrara, to which the waters have given a wonderful surface, gleams in unsullied freshness and beauty. Two tiny jets, set midway on either side between the ends of the fountain and the vase in the centre, bring an additional volume and add to the animation of the pool. The vase in the centre is represented in an old engraving by Falda as being much lower than the present one and carved in crowded leaflike convolutions, like the vase of the Scossa Cavalli fountain.