The second storey was octagonal and entirely filled by the spiral ascent. Above that was the circular third story, and above that the lantern. The lighting arrangements are uncertain. Visitors speak of a mysterious “mirror” on the summit, which was even more wonderful than the building itself. What was this “mirror”? Was it a polished steel reflector for the fire at night or for heliography by day? Some accounts describe it as made of finely wrought glass or transparent stone, and declare that a man sitting under it could see ships at sea that were invisible to the naked eye. A telescope? Is it possible that the great Alexandrian school of mathematics discovered the lens, and that their discovery was lost and forgotten when the Pharos fell? It is possible. It is certain that the lighthouse was fitted with every scientific improvement known to the age, that the antique world never surpassed it, and that the mediaeval world regarded it as the work of Jinns. Standing on the lantern was a statue of Poseidon. This terminated the tower, whose complete height certainly exceeded 400 feet and possibly touched 500. (2) HISTORY OF THE BUILDING. We must now follow this masterpiece of engineering into ages of myth and oblivion. It retained its form and functions unimpaired up to the Arab Conquest (A.D. 641). The first, and irreparable, disaster was the fall of the lantern (about 700), entailing the loss of scientific apparatus that could not be replaced. There is a legend that the disaster was planned by the Byzantine Emperor, who could not attack Egypt owing to the magic “Mirror,” which detected or destroyed his ships. He sent an agent who gained the Caliph’s confidence and told him that beneath the Pharos the treasure of Alexander the Great lay buried. The Caliph commenced demolition, and before the inhabitants of Alexandria, who knew better, could intervene, the two upper stories had fallen into the sea. Henceforth the Pharos is only a stump with a bonfire on the top. There were restorations under Ibn Touloun (880), and also about 980, but they were unsubstantial additions to the Octagon which the wind could blow away. Structural repairs were neglected, and about 1100 the second disaster occurred—the fall of the Octagon itself through an earthquake. The square bottom story survived, but only as a watchtower on the top of which was run up a small square Mosque. (_see_ Plan I, Fig. ii, which illustrates this state of the Pharos. The level of the ground has risen owing to the debris from the octagon, and the lower story has been buttressed). Then came the final earthquake (14th cent.) and the slow dissolution was over.