It is thus that the great centres of intercommunication, or vital points of our planet, as we should like to call them, become shifted in the course of time. Port Said, an improvised town on a desert shore, has thus become a centre of attraction for travellers and merchandise, whilst the neighbouring cities of Tyre and Sidon have dwindled down into miserable villages, with nothing to indicate the proud position they held in the past. Carthage, too, has perished, and Venice decayed. Many a thriving place on the shores of the Mediterranean has been reduced to insignificance through the silting up of its harbour, the employment of larger vessels, the loss of independence, or through political changes of all kinds. But in nearly every instance some neighbouring town has taken the place of these decayed harbours, and most of the great routes of commerce have maintained their original directions, and their terminal points, as well as intermediate stations, have remained in the same localities. There are, moreover, certain places which ships are almost obliged to frequent, and where towns of importance arise as a matter of course. Such are the Straits of Gibraltar and of Messina; such, also, are places like Genoa, Trieste, and Saloniki, which occupy the bottom of gulfs or bays penetrating far into the land. Ports offering the greatest facilities for embarking merchandise intended for foreign countries, such as Marseilles and Alexandria, are likewise natural centres of attraction to merchants. One town there is in the Mediterranean which enjoys at one and the same time every one of the geographical advantages which we have pointed out, for it is situated on a strait connecting two seas and separating two continents. This town is Constantinople, and despite the deplorable maladministration under which it suffers, its position alone has enabled it to maintain its place amongst the great cities of the world. The ports of the Mediterranean no longer enjoy a monopoly of commerce as they did for thousands of years, but the number of ships to be met with in that inland sea is, nevertheless, proportionately far greater than what we meet with on the open oceans. The commercial marine of the Mediterranean numbers thirty-seven thousand vessels, of a capacity of two million seven hundred and ninety-six thousand tons, without counting fishing-boats. This is more than one-fourth of the entire commercial marine of the world, as respects the number of ships, and one-sixth of it as regards tonnage. This inferiority of tonnage is due to the small vessels of ancient types which still maintain their ground in Greece and Italy, and which possess certain advantages for the coasting trade.