After the dissolution of the great Macedonian Empire comprising territories in the three Continents, the germs which the uniting and combining system of the government of Alexander had deposited in a fruitful soil, began to develop themselves every where, although with much diversity of form. In proportion as the national exclusiveness of the Hellenic character of thought vanished, and its creative inspiring power was less strikingly characterised by depth and intensity, increasing progress was made in the knowledge of the connection of phenomena, by a more animated and more extensive intercourse between nations, as well as by a generalisation of the views of Nature based on argumentative considerations. In the Syrian kingdom, by the Attalidæ of Pergamos, and under the Seleucidæ and the Ptolemies, this progress was favoured and promoted every where and almost at the same time by distinguished sovereigns. Grecian Egypt enjoyed the advantage of political unity, as well as that of geographical position; the influx of the Red Sea through the Straits of Bab-el-Mandeb to Suez and Akaba, (occupying one of the SSE.-NNW. fissures, of which I have elsewhere spoken), bringing the traffic and intercourse of the Indian Ocean within a few miles of the coasts of the Mediterranean.

The kingdom of the Seleucidæ did not enjoy the advantages of sea traffic, which the distribution of land and water, and the configuration of the coast line, offered to that of the Lagidæ; and its stability was endangered by the divisions produced by the diversity of the nations of which the different Satrapies were composed.