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 ⅝ of a yard to a yard in width, and from 1 to 3 yards in height, according to the hardness of the rock. [Illustration: Aqueduct near Tunis, leading to Ancient Carthage] 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.