5. _The Height of the Inundations._—The just height of the inundation, according to Pliny, is sixteen cubits.(290) When it rises but to twelve or thirteen, a famine is threatened; and when it exceeds sixteen, there is danger. It must be remembered, that a cubit is a foot and a half. The emperor Julian takes notice, in a letter to Ecdicius, prefect of Egypt,(291) that the height of the Nile’s overflowing was fifteen cubits, the 20th of September, in 362. The ancients do not agree entirely with one another, nor with the moderns, with regard to the height of the inundation; but the difference is not very considerable, and may proceed, 1. from the disparity between the ancient and modern measures, which it is hard to estimate on a fixed and certain foot; 2. from the carelessness of the observers and historians; 3. from the real difference of the Nile’s increase, which was not so great the nearer it approached the sea. As the riches of Egypt depended on the inundation of the Nile, all the circumstances and different degrees of its increase had been carefully considered; and by a long series of regular observations, made during many years, the inundation itself discovered what kind of harvest the ensuing year was likely to produce.(292) The kings had placed at Memphis a measure on which these different increases were marked; and from thence notice was given to all the rest of Egypt, the inhabitants of which knew, by that means, beforehand, what they might fear or promise themselves from the harvest. Strabo speaks of a well on the banks of the Nile near the town of Syene, made for that purpose.(293) The same custom is observed to this day at Grand Cairo. In the court of a mosque there stands a pillar, on which are marked the degrees of the Nile’s increase; and common criers every day proclaim, in all parts of the city, how high it is risen. The tribute paid to the Grand Signior for the lands, is regulated by the inundation. The day on which it rises to a certain height, is kept as a grand festival, and solemnized with fire-works, feastings, and all the demonstrations of public rejoicing; and in the remotest ages, the overflowing of the Nile was always attended with an universal joy throughout all Egypt, that being the fountain of its happiness. The heathens ascribed the inundation of the Nile to their god Serapis; and the pillar on which was marked the increase, was preserved religiously in the temple of that idol.(294) The emperor Constantine having ordered it to be removed into the church of Alexandria, the Egyptians spread a report, that the Nile would rise no more by reason of the wrath of Serapis; but the river overflowed and increased as usual the following years. Julian the apostate, a zealous protector of idolatry, caused this pillar to be replaced in the same temple, out of which it was again removed by the command of Theodosius.