an apprehension, that making the five principal arches semi-circular, he would considerably add to the expense. In the rest of the edifice, much judgment has been displayed ; no part of it has failed, or appears to have received the least injury. This aqueduct was finished in 1738. The great earthquake, which in 1755, destroy- ed thousands of lives, in Lisbon, numerous houses, palaces, and churches, and shook all the peninsula, had no effect upon this noble structure, which continued to pour its waters into the ruined city, with the same equal flow, after, as before that great catastrophe. Over the arches there runs a vaulted corridor, 9 feet 6 inches high, by 5 feet broad internally. A continued passage runs through the centre of it, for the people who con- stantly attend to keep it in order, and a semi-circular channel or conduit of 13 inches di- ameter at each side, through which the water is conveyed. It is worthy of remark, that these channels are laid not in an inclined direction, as in other aqueducts, but horizontal- ly ; to compensate for this, a small depression is made, at certain intervals, by which the water is impelled along the horizontal line , a manner, supposed by the natives, to require less declension in conveying water than an inclined line. There are two thoroughfares for foot passengers along the aqueduct, one at each side of the corridor, which is 5 feet 18 70 PREL1MINARYESSAY. wide, defended by a stone parapet. From some remains of the Romans on this spot, it is supposed they either did, or attempted to, construct an aqueduct in this situation. The honor of erecting this noble structure is due to John V. This munificent prince laid the foundation of it in 1713, and in thirteen years the whole was completed. The city of Lisbon, in testimony of gratitude raised an arch to his memory, bearing a flattering inscription, in the Latin tongue, importing that he had not only conferred wealth, glory, strength and peace on his kingdom, but that, overcoming nature as it were, he had introduced perennial waters into the city, and hailing him therefore as the best of princes, and the author of a great and useful public work. Manuel dal Maga was the architect, and the expense was defrayed in part, by a tax of one rei, something less than one tenth of a cent, on every pound of meat sold in the capital. Murphy, in his travels, in recording this fact, states the quantity of butchers meat sold in Lisbon, in the year 1789, at 12,212,160 pounds. " The consumption of flesh," he adds, " is greatly reduced here, by the quantity of fresh and salt fish with which the markets are constantly supplied."* It is singular that Murphy, who was an architect, should not have furnished details of the mode of construction, nor of the cost of this noble work, nor given any hint of the quantity of water brought into the city by it. The supply of this aqueduct is derived from the mountains of Cintra. Its course is between 8 and 9 miles, and it terminates in the city, in a Chateau d'Eau or Castel- lum, whence the waters are distributed to numerous fountains. Lisbon is built upon the slope of a hill, over the top of which, the waters of the aqueduct are introduced. Lofty, therefore, as are the houses, there is head enough to carry a supply up to the attics, yet here, as in Rome, not a pipe, as is believed, is laid to any house in the city ; a corps of water carriers, of Spanish descent, and from their province of Gallicia, taking the name of Gallegos, effect the distribution of the bountiful outpouring of this noble aqueduct, and are to be seen at all hours of the day, toiling up the stone stairways of the loftiest houses, bearing on their head or shoulders, an earthen vase, containing almost a barrel of water. With this grandest of modern European aqueducts, we terminate our notice of such constructions in the Old World, and turn to America, where, earlier than is recorded, aqueducts have existed. AMERICAN AQUEDUCTS. In the southern portion of our continent, a race more civilized than any of the aboriginal inhabitants of that portion of America, now constituting the United States, * Murphy's Travels in Portugal, 4to ed., p. 183. PRELIMINARY ESSAY. 71 had constructed extensive conduits or aqueducts, for the irrigation of their arid soil, and in some cities, for culinary and other domestic use. Humboldt and Garcilasso de la Vega, speak with admiration of the aqueducts of Peru. Garcilasso, who was a Peruvian by the mother's side, and who wrote his Com- mentaries in 1560, records of Viracocha, the seventh