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.
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.