on a continuous line for many miles, with a regular inclina- tion from the source to the city, but are interrupted by re- versed syphons. Instead of crossing deep and wide valleys in the usual manner of stone structures, the Aqueduct termi- nates on one bank in a reservoir or cistern, and a pipe is laid from it down the sloping side of the hill to a stone pier erected at a suitable distance ; the pipe rises up the pier to the top where the water is discharged into a small cistern 28 nearly as high as that in the reservoir. From the cistern, another conduit pipe descends to the bottom of the pier, passes along the ground to a second pier at a proper dis- tance and rises to another cistern on the top of it, and so on till it rises on the crest of the opposite bank, where the water resumes its regular motion along the Aqueduct. This plan was probably adopted with a view to avoid the expense of constructing a bridge which should preserve the general inclination of the channel-way ; but it is difficult to imagine any advantage arising from the construction of the piers, instead of laying the pipe along the bottom of the valley. Modern Rome. Rome is now supplied with water by three Aqueducts, being three of the ancient works restored in modern times. First, Aqua Virgini, called by Frontinus, Aqua Virgo, or Virgin Aqueduct. The trunk of the Aqueduct having been injured, the repa- ration was began under the Pontificate of Nicholas V. and Sextus IV., and completed under that of Pius IV. in 1568. This water supplies the beautiful fountain Trevi, thus named from the three discharges issuing from it, or from its being placed at the junction of three streets. The water this Aqueduct furnishes is 2,322,762 cubic feet (14,168,848 gal- lons) daily, discharging through 7 principal conduits, at 13 public and 37 other fountains. 29 Second, Aqua Felice. This is a part of the ancient water of the Claudian and Marcian Aqueducts united with many others, and collected under Sextus V. The daily quantity it furnishes is 727,161 cubic feet, (4,435,682 gal- lons,) and supplies 16 public and 11 other fountains. The Moses fountain discharges from this source. The Pauline Aqueduct, called Aqua Paola, is the third of the ancient works restored. The water is collected within the territories of Arcolo and Bassano, and conducted along the ancient Aqueduct of Alsietina. This was effected under Pope Pius V., and directed by Charles Fontana, an eminent Hydraulic Architect, who constructed the great fountain of S. Pietro-in-Montorio. Additional water was also taken from Lake Bracciano by Fontana in 1694, under Clement X. The whole quantity in 24 hours is 3,325,531 cubic feet, (20,285,739 gallons,) about one third of which goes to feed the fountains of St. Peters, and those of the Pontifical Pal- ace on the Vatican Hill ; the rest is distributed among 8 public and 23 other fountains, as well as to 21 work-shops, (usines) in St. Pancras-street. An evidence of the durability of these old Roman struc- tures is furnished in this junction of water from Lake Brac- ciano by Cardinal Orsini, under authority of Clement X., upon condition that a part of the water should be used to feed a second fountain about to be built in St. Peter's Square at Rome, and the rest to be divided between the Apostolic Chamber and the House of Orsini. From the lake the con- duit leads to the old Alsietina Aqueduct, in which it flows 20 8 30 miles to the city, and it was found to be in so perfect a state when the trial was first made after the restoration, October 13th, 1693, that all the water which entered the old Aqueduct was discharged at Rome without any loss, after its use had been suspended nearly 1000 years. The Principal Modern Aqueducts of Italy, France, Etc Aqueduct of Caserta. This Aqueduct was built by the order of the King of Na- ples, Charles III., for conducting water to his residence which he had at Caserta, a town situated about fifteen miles north of Naples. This Aqueduct was commenced in 1753. It is twenty- seven miles long, from the sources which supply it to the gardens of Caserta. The sources are at the base of the mountain called Taburno; the principal one is called Sor- gente de la Sfizzo; it is afterwards joined by streams from many other sources, which are in the country called Airola. These waters are all joined in one Aqueduct, crossing the river Faenza, upon a bridge of three arches, built in 1753. Again, in the valley of Durazzano, there is another bridge of three arches, upon which the Aqueduct crosses