Part 2

The third Aqueduct was built by the Emperor Claudius to furnish water to the palace of the emperors situated upon an elevated mountain. The Aqueducts built at this era are all of the same construction; that is to say, from the plan and construction adopted by the Romans. A fourth Aqueduct was also constructed for this city, but there is some doubt whether it was built by the Romans.

AQUEDUCT OF MOUNT PILA.

This Aqueduct was built by Claudius, who was born at Lyons, to conduct water to the emperor’s palace, situated on the highest part of the city. The sources which supplied it, were in the neighbourhood of Mount Pila, and they were brought into the main Aqueduct by branch aqueducts. The main Aqueduct was forty miles in length; and adding the branches, the length of the Aqueduct was forty-five miles.

There were 13 bridges of stone to support the Aqueduct across valleys or over rivers, two of which were not built up to the plane of the Aqueduct, but were crossed by leaden pipes which descended on one side of the valley and, crossing the bridge, ascended on the opposite side. In another instance the pipes descended and crossed upon a wall of masonry and reached the opposite side of the valley. One instance, where pipes were used, will give an idea of their general form: the bridge was about 40 feet high and the perpendicular height of the Aqueduct above it was 140 feet. Nine leaden pipes of about 8 inches interior diameter and one inch thick were laid upon the inclined planes and across the level part of the bridge; thus communicating with the opposite crests of the valley.

These bridges which were constructed for the support of pipes, were wider in the bottom of the valley and also half way up the inclined plane, than they were for the remainder of the distance; and this form has suggested the idea that the pipes of 8 inches diameter, when they reached half way down the plane, separated, each one into two of 6 inches diameter which crossed the bridge, and converged into one again half way up the opposite plane. But it may be supposed that they continued of the same interior form throughout their length, and that this extra width was made for the purpose of giving an opportunity to fortify the pipes at the place where the pressure to which they were subjected was the greatest.

_Construction._

They commenced the construction by making a trench in the ground of sufficient dimensions for the masonry of the Aqueduct: upon the bottom of this trench was laid a mass of masonry 1 foot thick, upon which two walls were built, each 1½ foot thick and 5⅓ feet high, these walls standing 2 feet apart, and surmounted by a semicircular arch of a thickness of 1 foot and generally covered with earth 2 feet deep. The interior had a coat of cement plastering, 6 inches thick on the bottom and 1½ inch thick on the sides. The walls were constructed with small stones from 3 to 6 inches in thickness, bedded in mortar so that no spaces could be found between them. They avoided the use of stones of greater thickness than 6 inches, because the walls built of small stones, well filled with mortar, formed a mass more solid and impervious than with larger stones, on account of the great quantity of mortar used.

No bricks were used in the construction of the channel-way of the Aqueduct.

Ventilators were constructed along the course of the Aqueduct 2 feet square, and rising above the ground 2 or 3 feet. The Aqueduct when it was above the ground, was supported upon a wall of masonry, and the side walls of the channel-way had an increased thickness. When it was elevated 6 or 7 feet above the ground, the foundation wall was six feet thick; but when it had a greater elevation it was supported upon arches and piers, and upon the elevation depended the span of the arch, the thickness and height of the piers. The general declivity in the channel-way, was 1 foot in 640, or about 8¼ feet per mile.

This Aqueduct supplied about 1,200,000 gallons of water in 24 hours. The velocity of the water was about five times that of the water in the Aqueducts of Rome.

This work was constructed at an immense expense, and in substituting the “_inverted syphon_,” for high structures across valleys, there is evidence of the intelligence and skill of those who had charge of the construction.

A fragment of a pipe forming part of this reversed syphon, is still preserved in the museum at Lyons, and an instance of the Romans having laid pipes across the beds of rivers, is given by M. Gautier, Architect, Engineer, &c., in his work called “_Traité de la Construction des Chemins_,” published in 1778.

About 70 or 80 years ago, he was directed by Mr. Pontchartrain, Minister of State, to repair to Rochefort, to conduct spring water to the port from the fountains of the city, which were supplied from a source, though quite insufficient for the city, in the neighborhood. In his researches he discovered a good and copious source, at less than half a league, but on the other side of the river, the Charente. Many difficulties were presented, because at low water vessels might ground upon the pipes and injure them.

However, Mr. Gautier proposed to lay down two leaden pipes, to preserve a supply in case of accident to one, and to protect them by wooden frames in an effectual way against injury, should vessels lay upon the defence frames during low water. Mr. Begon, intendant of the Marine, approved the plan, but it was finally rejected.

“Some years after,” says Mr. Gautier, “when I had charge of the roads on the Rhone, and of many other works in the Province of Languedoc, and while at Arles, I heard that a vessel had cast anchor in the Rhone, opposite the city, to take some loading; but when the commander wanted to sail again he could not raise the anchor. This fact attracted much attention, and many people went to witness the singular circumstance. The Captain, unwilling to lose his anchor, sent down a man, to find what was the matter. The diver reported that the anchor was hooked under something round, but he could not tell what it was. A capstan was applied to raise it, which succeeded.

It brought up a leaden conduit pipe from the bottom of the Rhone, which crossed it from the City of Arles, towards Trinquetaillade, over a breadth of about 90 toises (576 feet) in a depth of 6 or 7 toises (about 40 feet,) the deepest part of the Rhone. I saw some pieces of this conduit of lead, 5 or 6 inches in diameter, about 4 lines (one third of an inch) thick, in joints of 1 toise each soldered lengthwise, and covered by a strip or sheet of lead of the same thickness covering the first solder about 2 inches. The conduit was soldered at the joints, 6 feet apart, by the same material, which made a swell at that distance. On each joint were these words in relief =C. CANTIUS POIHINUS. F.= which was apparently the name of the maker or architect, who laid down the conduit pipe in the time of the Romans. I delayed not to inform Mr. Begon, at Rochefort, of this discovery, because he had always favoured my project of conducting water along the bottom and across the Charente, which would not have been half so difficult as it had no doubt been, to lay one across the Rhone where this was found.

Hence it may be believed, as I think now myself, that many things supposed now-a-days to be new and never to have been previously invented, may have been thought of long before, even in remote ages.” Pp. 129, 130.

_Ancient Aqueduct of Metz._

This Aqueduct was built by the Romans when that city was under their dominion; but it is difficult to fix upon the precise era of its construction. It is said in the history of the city of Metz that the Roman legions built roads in the year 70; but there is reason to suppose that the construction of this Aqueduct, as well as that of other important structures built by the Romans at Metz, belongs to a time more remote, and that the date of the reign of the first emperors may be the era when the legions of Cæsar occupied the country of the Gauls.

The total length of the Aqueduct was 14 miles, and the fall for this distance was about 73 feet.

The channel-way was 6⅓ feet high, by 3 feet wide, constructed with stone masonry and having an arch over the top: the interior face of the walls and the bottom was covered with a coat of plastering; 3 inches thick in the bottom, and 2 inches on the sides. From remains of this Aqueduct which are now found at various points along its course, it appears to have required many expensive structures for crossing valleys; in one instance the Aqueduct bridge was 3,600 feet long, and the greatest height was 100 feet. In constructing the Aqueduct over these bridges, they formed it in two channels separated by a wall, and each covered with an arch; thus they insured a supply of water across the bridge by one channel in case the other required repairs.

_Aqueduct of Bourgas, near Constantinople._

Three Aqueducts exist in the valley of Bourgas, 8 miles from Constantinople, for conducting water into the city. One of them is remarkable for the beautiful architectural arrangement and the solidity of its construction. It is 115 feet high, and was built under the Emperor Justinian, A. D. 527. It has two ranges of arches, one above the other, and the Aqueduct supported upon the second. These Aqueducts are in some parts unlike those of Rome, which were formed on a continuous line for many miles, with a regular inclination from the source to the city, but are interrupted by reversed syphons. Instead of crossing deep and wide valleys in the usual manner of stone structures, the Aqueduct terminates 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 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 distance 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 reparation 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 gallons) daily, discharging through 7 principal conduits, at 13 public and 37 other fountains.

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 gallons,) 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 Palace 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 structures is furnished in this junction of water from Lake Bracciano 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 conduit leads to the old Alsietina Aqueduct, in which it flows 20 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 Naples, 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 _Sorgente 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 _Faënza_, 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 the valley, passing over the river, and extending from the mountain called _Santa Agata de’Goti_, to the mountain of _Durazzano_.

This Aqueduct afterwards crosses a deep valley, which it meets between _Monte-Longano_ and the hills _Tifata_, where ancient Caserta is situated, about the place called _Monte di Gazzano_. The crossing of this valley required the most important of all the constructions connected with the work. It was accomplished by an Aqueduct bridge, 1724 feet long and 190 feet in height, composed of three tiers of arches, one above another. The lower range has nineteen arches, the middle twenty-seven, and the upper one forty-three; making in all eighty-nine arches.

The labor of constructions under ground for this Aqueduct was more than that above; it pierced through five hills or mountains, making an aggregate length of tunnel of about four miles, and most of this was through rock.

To give air and light to the channel, they made pits or wells; some of which were 250 feet deep, 10 feet diameter at the bottom, and 4 at the top.

_Aqueduct Bridge of Castellana._

This Aqueduct was built in connection with an ancient _Causeway_, which led to _Civita-Castellana_.

This _Causeway_ was about 820 feet long and 32 feet wide; the greatest height was about 130 feet. It was pierced in the middle of this extent, by nine large arches; three of which were 86 feet span, and the others were each 64 feet span. Above these arches of the bridge the Aqueduct is built, the height of which is about 57 feet, and it is sustained upon a series of arches of about 19 feet span each.

_Aqueduct of Montpelier._

This Aqueduct is one of the most beautiful works of the kind, which exist in France. The length is about 3,200 feet; it conducts to Montpelier the waters of _Saint Clement_ and _du Boulidou_. It was built by M. Pitot, engineer and member of the Academy of Sciences. He was thirteen years constructing it. This Aqueduct is formed by two ranges of arches; those in the lower tier are seventy in number, and each 28 feet span; the piers of these arches are each 12 feet thick. The arches of the second or upper tier are much smaller, and are arranged so that three of them come within the space occupied by one of the lower arches. They are 9 feet diameter; their piers are 4 feet and a quarter thick.

The greatest height of this Aqueduct is 90 feet.

It is constructed entirely of cut stone. The quantity of water furnished by it is about 300,000 gallons in twenty-four hours.

_Aqueduct of Spoleto._

This Aqueduct was constructed in the year 741, by Theodoric, King of the Goths, to communicate with the town of Spoleto, situated upon the summit of a mountain. It is composed of ten grand Gothic arches each 71 feet diameter, supported upon piers of 10½ feet thickness. The middle arches which are over the river _de la Morgia_, are about 328 feet high.

On the top of this bridge is the Aqueduct which carries the water to Spoleto.

This structure was difficult to execute, and being built of a very hard stone, remains entire at the present day.

The total length is 800 feet, and the breadth is 44 feet.

The greatest height of this bridge is 420 feet.

_Aqueduct of the Prince of Biscari._

This Aqueduct was constructed by the Prince of Biscari, in Sicily, at his own expense, across the river Saint-Paul, the ancient _Symète_. It conducts a pure stream of water to the estate of the prince, and at the same time serves as a public bridge over the valley. This bridge is composed of thirty-one arches, the largest of which, over the river, is 90 feet span. This arch is of Gothic form, while all the others are semi-circular. The bridge has two tiers or ranges of arches; the roadway is upon the first range, and the channel for the water, upon the second or upper range. The length of the bridge is 269 feet. The height to the top is 120 feet. It is said that this magnificent structure was accomplished in two years.

_Aqueduct of Arcueil._

The Emperor Julian built this Aqueduct to bring water to Paris, A. D. 360; it supplied the palace and hot baths, but was destroyed by the Normans. It was above nine miles and a half long, and was entirely under ground, except the stone arcade over a deep valley at Arcueil. After its use had been suspended 800 years, a new and beautiful arched Aqueduct was built by the side of the ruins of the old one, and its final restoration to public use was completed in 1634.

Part of this ancient construction, consisting of two arches substantially built, still exists, near the modern Aqueduct.

The Aqueduct bridge over the valley of Arcueil has twenty-five arches, is 72 feet high and 1,200 feet in length.

In the interior of the Aqueduct on each side is a parapet which forms a walk. On the outside along the whole line are various openings, called _regards_.

This Aqueduct was thoroughly repaired in 1777; and fresh sums of money have lately been devoted to the same purpose by the city of Paris. It supplies 36,000 hogsheads daily.

_Aqueduct of Maintenon._

This work, had it been completed, would have been one of the most remarkable of modern times. The project was one of the noblest examples of the enterprise which characterized the reign of Louis XIV., and had it been carried out would have presented a work equal in grandeur to any of the kind constructed by the Romans. It was projected by Vauban, and the work was commenced in 1684, but was abandoned in 1688.

It was intended to conduct water from the river Eura to Versailles; a distance of over seventy miles; and it was also contemplated to continue the work to St. Cloud and to Paris; had this been done it would have been over ninety miles in length. It was intended to be of a mixed construction; partly by a canal formed by excavations and embankments, and partly by a channel of masonry.

One of the most remarkable structures connected with it, was the Aqueduct bridge across the valley of Maintenon. This was designed to be entirely of masonry, having three ranges of arches, one above another. The length of this Aqueduct bridge would have been three and a quarter miles, and the height from the lowest part of the valley would have been 234 feet.

The whole number of arches designed for this bridge was 685.

Some of the piers and arches of the lower tier were constructed, but have since been suffered to crumble and fall. Many deep valleys were filled with embankments, and the canal was completed for a portion of the distance, but the course of the work is now but faintly marked by the remains of these structures.

_Aqueduct of Lisbon._

The site of Lisbon, as well as the ground in its vicinity, consists chiefly of limestone and basalt, which render it necessary to obtain good water, at about three leagues distance, for the beverage, and other uses of the inhabitants. The source consists of several springs that are near to the village of Bellas, and their produce is conveyed to Lisbon by an Aqueduct, constructed of a kind of white marble, and finished in 1738. In some parts its course has been excavated through hills; but near to Lisbon it is carried over a deep valley, for a length of 2400 feet, by means of several bold arches, of which the largest has a height of about 250 feet, by a breadth of 115. The arches being pointed have an interesting aspect, particularly when viewed from below, the interior of the spacious vaults being not only majestic in appearance, but reverberating every sound. The water flows through a stone tunnel, or covered arch-way, about 8 feet wide, formed in the middle of the structure; and on each side there is a foot-path, with a parapet wall, having a sufficient width for two persons to walk. The Aqueduct enters the town on its northern side, at a place called da Amoreira, where it branches into several others, in order to supply the different fountains, from which the inhabitants are supplied. Persons, denominated _gallegos_, obtain a subsistence by selling the water, which they procure at the fountains in small barrels, and afterwards cry it through the streets.

_Aqueducts of Mexico and the adjacent States._

The people who, in remote times, inhabited the region of Mexico, were advanced in civilization and in the arts; they had regularly organized states and established forms of government, and their immense cities, their roads, Aqueducts and other public works, give evidence of the advanced state of the arts among them and their knowledge of the sciences.

The location and great population of some of their cities required a familiar knowledge of hydraulic operations to supply them with water; and hence it would seem as if they had cultivated this department of the arts equally with others, for some of their Aqueducts were of a character that would have done honor to Greece or Rome. Nearly all the ancient cities of Mexico were supplied by them.

“The city of _Mexico_, which was built on several islands near the shore of the lake, was connected to the main land by four great causeways or dikes, the remains of which still exist. One of these to the south, the same by which Cortez entered, was nearly two leagues long--another to the north about one league, and the third at the west somewhat less. The fourth supported the celebrated Aqueduct of Chapoltepec, by which water was conducted from springs, upon an insulated hill of that name, at the distance of from two to three miles.”

The Aqueduct of Chapoltepec was the work of Montezuma, and also the vast stone reservoir connected with it.

This Aqueduct consisted of two conduits formed of solid mason work--each five feet high and two paces broad--by which the water was introduced into the city for the supply of various fountains.