At the time of the exodus, therefore, it is evident that no canal could have existed in the valley of Goshen. The population of Israelites and Nomads, however, which dwelt on the confines of the irrigable land, must have been very great; as the Hebrews alone exceeded 600,000 souls, and they were accompanied by "a mixed multitude," which is the phrase used in Scripture to designate the nomad Arabs. But though no canal existed at this period, we find evidence that a considerable trade in the produce of Egypt was already carried on through this district, caused by the want of agricultural produce in Arabia; and this trade induced the Egyptians to "guild for Pharaoh treasure-cities, Pithom and Raamses."[1] [1] Compare Genesis, xlvii. 11, Exodus, i. 11, and xii. 37. As soon as the children of Israel were driven out of the land of Goshen, the new occupants would naturally commence the formation of a canal, for irrigating the land they had gained. Now, a great part of the valley of Seba Biar is lower than the level of the Nile at the height of the inundation, this was easily done. A canal from the eastern branch of the river, near Bubastes, did not require to be cut to a greater distance than seven miles, in order to allow the waters to fill the valley. By this operation, the irrigation could have been carried as far as the northern boundary of the bitter lakes, between Suez and the Mediterranean; and at least 20,000 acres of land gained for agricultural purposes. This irrigation would extend itself to the Serapeion--a distance of about forty-five miles from Bubastes, and about forty from the Red Sea. Let us now observe the chronology of the events we have already noticed. Without pretending to offer any opinion on the disputed questions of Egyptian chronology, we shall adopt the dates given by Dr Nolan in his memoir on the use of the ancient cycles in settling the differences of chronologists, published in the Transactions of the Royal Society of Literature.[1] It must be observed, that the 430 years of the sojourning of the children of Israel in Egypt is to be computed from the call of Abraham, and not from the going down of Israel, as is explained by St Paul in the Epistle to the Galatians, chap. iii. v. 17.[2] [1] Vol. iii. p. 2. [2] Josephus, Antiquit. Jud. ii. 15, 2; Clinton's Fasti Hellenici, i. 297. The administration of Joseph occurred during the reign of the last king of the race of the Hyksos, B.C. 1687 The reign of Mephres, or Moeris, B.C. 1538 The exodus occurred in the year B.C. 1492