The storage of water in cisterns or reservoirs is by no means a modern practice. The earliest tribes of whom we have any traditions or records resorted to this method for providing a supply of water. In xi Kings, 18-31, the first mention is made of cisterns in "Drink ye every one the water of his cistern." The methods employed by the ancients to construct cisterns must have been laborious and unsatisfactory. Cement at that time was unknown and bricks were not made, so that the modern cistern, as we know it, could not have existed. No doubt in some localities where clay was plentiful the cisterns were scooped out of the earth and puddled with clay, just as many reservoirs of to-day are made. This method of constructing a cistern, however, would limit the form to a cup-shaped affair, which would be very difficult to roof over. If the cisterns were not covered, as much water might be lost by evaporation as would be used by the inhabitants, so that at its best a clay-puddled cistern must have been an unsatisfactory affair. In the locality of mountains and quarries, cisterns were hewn out of the solid rock. "They have forsaken me the fountain of living waters and hewed them out cisterns, broken cisterns that can hold no water."—Jer. 2-3. Rock-hewn cisterns must have made ideal storage reservoirs for water. The darkness of the cavern would prevent the growth of vegetation, while the thick walls of rock, affording a shelter from the sun, would keep the water cool and refreshing.

It is worthy of noting here that the ancients seem to have been aware of the movement of ground water through the soil, a fact that was forgotten and rediscovered in comparatively recent times. In Prov. 5-15 the statement, "Drink waters out of thine own cistern and running waters out of thine own well," would lead to this conclusion, unless, indeed, they classed a bubbling spring as a well.

The earliest known cistern or reservoir of which we have any authentic knowledge are the masonry cisterns or reservoirs that stored water for the supply of the ancient city of Carthage. These cisterns, which are wonderfully well preserved, are still to be seen on the site of the ancient Punic city, but outside of what was the walled city, before it was totally destroyed by the Romans.

These cisterns were originally covered with earth, and it is due to that fact, perhaps, that they escaped destruction when the Romans razed the city. It is easy to criticise the judgment of others, and no doubt if all the facts were known, there were good and sufficient reasons why the Roman general did not destroy the cisterns and cut off the supply of water from Carthage during the siege of that city. But in the light of our present knowledge of warfare, when a water supply is considered a vulnerable point, most carefully guarded by the besieged, and the point of most furious attack by the besiegers, when the fall of the city is considered almost accomplished when its water supply is taken, it seems an oversight on the part of the Romans not to have discovered and destroyed the cisterns, particularly as the destruction of everything in the city and environs was their mission at Carthage. It is an oversight, however, for which we may be thankful, since it preserved for future times an interesting engineering work of great magnitude for that period.

The cisterns of Carthage are eighteen in number, and each 100 feet long, 20 feet wide and nearly 20 feet deep. They lie in two long parallel rows and empty into a common gallery situated between the rows. From this center collecting gallery the water was delivered through conduits direct to the city of Carthage.

The earliest method of raising water from a well, cistern or other source of supply was by hand. This method, however, was laborious and unsatisfactory, particularly when necessary to raise large quantities of water for irrigation purposes, or to supply the inhabitants of a community at a great distance or high elevation, and it was not long before the mechanical ingenuity of our ancestors devised means for transferring this arduous duty to oxen, asses or other beasts of burden. Sometimes, as in the case of the Romans, this work is made a penal punishment, and persons found guilty of certain offenses were sentenced to the water-wheel.

About the earliest known device for raising small quantities of water was the pole and bucket, which was commonly employed in Italy, Greece and Egypt. The great antiquity of this method of raising water is proved by representations of it in Egyptian paintings. It consisted of a bucket attached to a pole that was suspended by trunnions so located that when the bucket was filled with water the thick end of the pole would just balance the combined weight of bucket and water. This permitted its use for many hours at a time, when raising water for irrigation without greatly fatiguing the operator.

The most ingenious and highly involved form of ancient water-raising machine was a water-wheel. The method of operating a water-wheel depended much on the region where used. In Egypt, along the Nile, oxen were employed for this purpose. In China, coolies were found more satisfactory even in raising large quantities of water for irrigation purposes, which they did by walking a simple form of treadmill on the outer edges of the water-wheel. The Romans, slow at originating, but, like the Japanese, quick to recognize the value of anything new and adapt it to their purposes, borrowed the idea of the water-wheel from the Greeks or Egyptians, but made it automatic when used in streams and rivers by adding paddles that dipped into the running water and were moved by the current of the stream. Water-wheels operated by oxen were in use at Cairo up to the twelfth century, where they raised water vertically a distance of 80 feet from the Nile to an aqueduct that supplied the citadel of Cairo.

Our present elaborate system of water distribution was of humble origin. It was not a rapid growth, but a gradual evolution. Its four principal stages were: First, distribution from natural sources by water carriers; second, aqueducts conveying water to communities where a system of sub-conduits or aqueducts conveyed the water from the main aqueduct to reservoirs at different points in a city; third, a system of distributing mains through which water was furnished to householders at certain hours only during the day; and fourth, our present system of continuous supply at all hours of the day and night. In the first stages of water distribution, water was carried on the backs of water carriers in earthenware jars constructed especially for the purpose, or in goat or other animal skins properly tanned and sewed to hold water. While this method of water distribution is of great antiquity, it is still practiced in most tropical countries, and to this day water carriers, some with the burdens on their backs, others with goatskins of water on donkeys' backs or with jars of water in two-wheeled carts, may be seen plying their trade in Mexican and Egyptian cities.

The earliest record we have of any effort to supply a community with water conveyed in tunnels or aqueducts from a great distance, dates from the year 727 B. C. King Hezekiah or Ezekias, who reigned in Jerusalem at that time, was much troubled over the poor quality of water furnished to the city and undertook to provide a better supply.

He had built at the gates of the city a vast reservoir, the "Pool of Siloam," but when it was completed, found that a sufficient quantity of water could not be had without conveying it from a distant source on the easterly side of a range of hills of solid rock, over which it would be impossible to convey it. In no way daunted he set to work to pierce the hills with a tunnel or aqueduct, capable of supplying the city with water. Work was commenced simultaneously at both ends of the tunnel and progressed uninterruptedly until the workmen met in the center under the mountain or hill. An inscription in old Hebrew characters, found close to Jerusalem and preserved in the Constantinople Museum, throws some interesting light on this, for that period, remarkable engineering work. Translated, the inscription reads: "The piercing is terminated. When the pick of one had not yet struck against the pick of the other, and while there was yet a distance of 3 ells, it was possible to hear the voice of one man calling to another across the rock separating them, and the last day of the piercing, the miner's pick met against pick. The height of rock above the heads of the miners was 100 ells. Then the water flowed into the reservoir over a length of 1,200 ells." This tunnel was cut through a mountain of solid rock. The tunnel varied in dimensions from ? of a yard to a yard in width, and from 1 to 3 yards in height, according to the hardness of the rock.

The magnitude of this undertaking can be realized only when it is considered that the tunnel was constructed without the aid of blasting agents, machine drills, steam, electricity or any of the great forces or devices now controlled by man and used in modern engineering construction.

At a later period in the world's history, Roman engineers, tunneling through the rock, used fire as well as chisels to disintegrate the rock. The usual method of procedure was to build an intensely hot fire against the rock, and when the rock had been heated to the right temperature it was drenched with cold water to crack and disintegrate it. According to Pliny, vinegar was sometimes used instead of water, under the impression that it was more effective in disintegrating rock.

It is doubtful if this method was used in constructing the tunnel at Jerusalem. In fact it can be stated with considerable assurance that the entire tunnel was cut by drilling and chiseling, as the tool marks are plainly discernible. It further is evident that, as stated in the tablet found near Jerusalem, the tunnel was worked from both ends until the miners met in the center. This is evidenced by the direction of the tool marks, which plainly show that the cutting on each side of the center was done in different directions.

Prior to the construction of the tunnel, the ancient city of Jerusalem was supplied with water through two aqueducts, one of which supplied water from the famous pools of Solomon, to the south of the city, and the other poured its contents into the pools of Hezekiah, outside the walls of the city.

The Greeks were the next in point of time to construct tunnels in connection with the building of aqueducts. In 625 B. C. the Greek engineer Eupalinus constructed a tunnel 8 feet broad by 8 feet high and 4,200 feet long, through which was built a channel to supply the city of Athens with water.

This period marks the beginning in Greece and Rome of a school of architects and engineers whose works have left a lasting impression on art and engineering science, and to this day are monuments of proportion and beauty of design that are studied by all students of architecture and engineering. It is quite probable that Greece supplied the first engineers that constructed aqueducts in Carthage and Rome. The similarity in design of these various works points forcibly to the conclusion that they were all designed by disciples of one school.

Whether the first aqueducts were built in Carthage or in Rome is a matter of some uncertainty, although the fact that an aqueduct supplied Carthage with water at the time it was destroyed by the Romans would point to the Carthagenian aqueduct as the prior. The first Roman aqueduct was built in the year 312 B. C., and the city of Carthage, which, after a protracted struggle of 118 years, from 265 B. C. to 147 B. C., was finally conquered and destroyed by the Romans, was at that time supplied with water from distant springs through an aqueduct.

It is quite probable that Carthage was supplied with water from two different sources. The cisterns already mentioned provided a supply of rain water for industrial and most domestic uses, while the aqueduct, the channel of which had a cross-section of 10 inches square, brought drinking water from springs in the Zaghorn Mountains, some 60 kilometers distant. The aqueduct contoured the hillside for a considerable distance, at times went under ground, and on approaching the city was carried on arches of magnitude seemingly out of proportion to the size of the channel. At present it is suffering the fate of most ancient ruins. It is used as a quarry from which stones are taken to construct buildings in nearby towns and villages.

While the ruins of aqueducts and tunnels at Jerusalem, Athens and Carthage give some idea of the skill and knowledge of hydraulic and sanitary matters possessed by the engineers of that period, we must turn to Rome and study their system of water supply, drains for sewage and the ruins of their magnificent baths to form a true conception of the skill of the early school of Roman engineers and the lavish expenditures of treasure by the inhabitants to secure an adequate water supply for Rome. No aqueducts were built in Rome before the year 312 B. C. Prior to that time the inhabitants supplied themselves with water from the Tiber or from wells, cisterns or springs. The first aqueduct was begun by Appius Claudius, the censor, and was named after him the Aqua Appia. This aqueduct had an extreme length of 11 miles, and almost all of the work was entirely under ground. Remains of this work no longer exist. After the Aqua Appia was completed the building of aqueducts seems to have become almost a habit of the Romans, and it was not long—272 B. C.—before M. Aurius Dentatus began a second one called the Anio Vetus, which brought water from the river Anio, a distance of 43 miles. This aqueduct was constructed of stone and the water channel was lined with a thick coat of cement—no doubt Pozzolana cement—made from rock of volcanic origin, which, upon being pulverized and mixed with lime, possessed the hydraulic property of setting under water. Indeed, there can be but little doubt that were it not for this natural cement the construction of Roman aqueducts would have been more difficult to accomplish.

The water furnished by the Anio Vetus was of such poor quality that it was almost unfit for drinking. A further supply being found indispensable, the Senate commissioned Quintus Marcius Rex, the man who had superintended the repairs of the two already built, to undertake a third, which was called after him the Aqua Marcia. This was the most pretentious aqueduct undertaken. It was 61 miles long, about 7 of which were above ground, carried on arches, and of such height that water could be delivered to the loftiest part of Capitoline Mount. A considerable number of the arches of this aqueduct are still standing. Remains are also standing of the Aqueduct Tepula (127 B. C.) and the Aqua Julia (35 B. C.), which, if we except the Herculea branch, are next in point of date. Near the city of Rome the three aqueducts were united in one line of structure, forming three separate water courses, one above another, the lowermost of which formed the channel of the Aqua Marcia and the uppermost that of the Aqua Julia.

Thirteen years after the Julia, the Virgo aqueduct was built. This aqueduct was 14 miles long and is said to be so named because the spring from which it is supplied was first pointed out by a girl to some soldiers who were in search of water. This aqueduct still exists entire, having been partly restored by Nicholas V and the work completed by Pope Pius IV in 1568.

In the tenth year of the Christian era, the Augusta aqueduct was built. This aqueduct was only 6 miles long, and the water that it brought from Lake Aluetimus was of such bad quality as to be scarcely fit for drinking, on which account it is supposed that the founder, Augustus, intended it chiefly for his naumachia.

It might be interesting at this point to deviate a little from the history of the Roman aqueducts and draw aside the curtain to catch a glimpse of the aquatic sports or pastimes of a Roman emperor of that period. The naumachia of Augustus was a rectangular basin 1,800 feet long by 1,200 feet wide, in which actual sea fights between rival fleets were held for the amusement of the emperor and his friends. The combatants in these sea fights were usually captives, or criminals condemned to death, who fought as in gladiatorial combats, until one party was killed, unless saved by the clemency of the emperor. The vessels engaged in the sea fight were divided into two parties, called respectively by names of different maritime nations, as Persians and Athenians. The sea fights were conducted on the same magnificent scale and with the same disregard of life as characterized the gladiatorial combats and other public games of the Romans held in the Colosseum. In Nero's naumachia, sea monsters were swimming around in the artificial lake to make short work of any poor unfortunate that was unlucky enough to go overboard.

In some of the sea fights exhibited by different emperors, the ships were almost equal in number to real fleets. In one battle there were 19,000 combatants and 50 ships on each side.

It was for the purpose then of supplying one of these artificial lakes with water that the Augusta aqueduct was constructed.

Perhaps the best known aqueducts of Rome are the Claudia and the Anio Novus. The completion of these waterways, which was accomplished respectively in 50 and 52 A. D., doubled the supply of water to Rome. The Claudia aqueduct was 46 miles in length and the Anio Novus 58 miles in length. The Claudia was commenced by Caligula in the year 38, but was completed, as was the Anio Novus, by the Emperor Claudius.

Many other aqueducts besides those mentioned were built at different periods to add to the water supply of Rome. A table is given below showing the date of the constructions and their lengths.

The magnificence displayed by the Romans in the construction of aqueducts was not confined to the capital. Wherever Roman colonies were established, it would appear that vast sums were expended in providing the community with a suitable supply of water. Ruins of aqueducts built by the Romans may still be seen at many points in Spain, France, Africa, Greece, and even England can point to the ruins of a water tower built by this prolific school of Roman engineers. At the present time there are probably one hundred or more structures of this kind in existence, some of which are in daily use, supplying water to inhabitants of communities for whose ancestors they were built centuries ago.

ROMAN AQUEDUCTS, ARRANGED IN CHRONOLOGICAL ORDER

(The miles above given are Roman miles, of 4,854 feet. The entire length of aqueduct in English miles would be 398.)

The aqueduct of Segovia, Spain, is one of the most perfect and magnificent works of the kind remaining. It is built without mortar, is entirely of stone and of great solidity. The piers are 8 feet wide by 11 feet deep, and where the aqueduct approaches the city it attains a height of about 100 feet. This aqueduct is over 2,400 feet long, is built in two tiers of arches and although almost eighteen hundred years old, still supplies water to the city. Of the 109 arches, however, 30 are of modern construction, being reproductions of the ancient arches.

The constructive details of these old water courses are as interesting as are their general design. At the mouth of each aqueduct there generally was constructed a reservoir in which to collect water from the springs or streams that supplied it, and in which impurities could settle before the clarified water was delivered into the channel. The water channel was usually formed either of stone or brick coated on the inside with cement to make it water-tight. It was arched over on top, and at certain intervals vent holes were provided through which access could be had to the channel to make repairs. When two or more channels were carried one above another, the vent holes of the lower ones were placed in the sides. When possible, aqueducts were carried in a direct line, but frequently they were given a tortuous course either to avoid boring through hills, where their construction would have entailed too great expense, or else to avoid very deep valleys or soft marshy ground. In every aqueduct, besides the principal reservoirs at its mouth and terminal, there were intermediate ones at certain distances along its course, in which any remaining sediment might be deposited. In addition to serving as sediment basins, these reservoirs made it more easy to superintend and keep in repair the different sections, and provided service reservoirs to furnish irrigation water for fields and gardens and water for stock. The principal reservoir was that in which the aqueduct terminated. This reservoir or castella, as it was called, far exceeded any of the others in grandeur of architecture, or in magnitude and solidity of construction. The ruins of a work of this kind that still exist on the Esquiline Hill at Rome, are about 200 feet long by 130 feet wide, and had a vaulted roof that rested on 48 immense pillars disposed to form rows so as to form 5 aisles and 75 arches. From the description of this interesting reservoir, the interior must have greatly resembled many of the covered slow-sand fillers recently constructed in this country, in which elliptical groined arches form the roof, which is carried on brick columns spaced as in the reservoirs at Rome, about 15 feet from center to center. Judging from the fact that not only the aqueducts but also the reservoirs were covered to exclude light, it seems reasonable to conclude that Roman engineers were aware that absence of light prevented or altogether checked the growth of algÆ and other objectionable forms of water vegetation. Nowhere in the writings of the early historians is any mention made of trouble due to this cause, but as the water supply of Rome was obtained from both ground (spring) and surface sources, which in many cases were mixed together, the resultant mixture would have furnished the best possible soil for algÆ, the ground water providing the necessary mineral food and the surface water furnishing the seed. It is quite probable, therefore, that the aqueducts and reservoirs were covered to prevent such growths.

Besides the principal reservoir, each aqueduct had a number of smaller ones at different points in the sections they supplied, to provide that neighborhood with water. It is estimated that all told there were 247 of the auxiliary public reservoirs scattered throughout the city. These reservoirs were supplied from the principal reservoir through pipes of lead, burned earthenware, and in some cases bored out blocks of stone. Burned earthenware pipes were generally used not only on account of their greater cheapness, but because the Romans were aware of the injurious effect of lead poisoning, and looked with suspicion on water that had been conducted through lead pipes.

When a number of individuals living in the same neighborhood had obtained a grant of water, they clubbed together and built a private reservoir into which the whole quantity allotted to them collectively was transmitted from the public reservoir. The object of private reservoirs was to facilitate the distribution of the proper amount of water to each person and to avoid puncturing the main aqueduct in too many places. When a supply of water from the aqueduct was first granted for private use, each householder granted the privilege obtained his quantity by tapping a branch supply pipe into the main aqueduct, and conducting the branch to a domestic reservoir within his own house. Later when the system of private reservoirs was adopted, each domestic supply of water was obtained from the private reservoir and piped to the domestic reservoir which was made of lead.

The faÇade of an aqueduct reservoir known as the "Trophies of Marius" may be seen in the accompanying reproduction of a woodcut made in the sixteenth century. The ground plan shows part of the internal construction. The stream of water is first divided by the round projecting buttress into two courses which are again sub-divided into five minor streams that discharge into the reservoir as indicated in the cut.

The quantity of water supplied to Rome compared favorably with the per capita allowance of water provided at the present time for the principal cities of the United States, and was far in excess of the water supplied at the present time to British and European cities. According to Clemens Herschel, however, Rome, with a population of 1,000,000 people, had a daily water supply of only 32,000,000 U. S. gallons. In estimating the quantity of water brought to the city by the system of aqueducts, Mr. Herschel makes due allowance for and deducts what he thinks might be lost by leakage, theft, water supplied to artificial lakes for sea fights, and also assumes that a certain percentage of the channels at all times were cut out of service for repairs. He makes no allowance, however, for water obtained from different sources, such as wells, springs and the Tiber River, from which, no doubt, many of the inhabitants obtained their entire supply of water. Indeed, in the year 35 B. C., M. Agrippa, as the head of the water supply system of Rome, in addition to repairing the Aqua Julia and Marcia aqueduct, supplied the city with 700 wells and 150 springs.

There is no reason to believe that conditions in Rome were different from those existing to-day in our large cities, and it is more than probable that the poor people of Rome were but scantily supplied with water from the aqueducts. The supply obtained by them from ground sources should therefore be added to that supplied by the aqueducts, and it would then be found, as most writers assert, that the per capita daily supply of water to Rome was equal to about 100 U. S. gallons.

Such enormous quantities of water could not be poured daily into a limited area without material and physical injury resulting if provision were not made to dispose of the surplus. Hence it was that a system of drains was evolved in Rome, which, while not the first in point of time, nevertheless were the only ones known to have been constructed by the ancients, until within a comparatively recent date ruins of sewerage systems were unearthed in Bismya, an ancient Symerian or pre-Babylonian city.