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. [Illustration: Water Carrier with Goat-skin Bag]