The torrid zone contains nearly a third of the land surface of the earth, and only a quarter of its population; the density of population is thus below the average. Original civilisations have existed in the torrid zone——for example, Mexico and Peru before the arrival of Europeans——but these existed on higher plateaus where the climate was not tropical. There were civilisations in India and the East Indies, but these were imported from the valley of the Ganges. There are to-day intertropical countries which exhibit an active economic life: India, Mexico, the Antilles and the seaboard of Brazil. Nevertheless, in the greater part of the torrid zone it would seem that the continuous high temperature saps human energy, and also renders it to a great extent unnecessary, by simplifying life, reducing as it does the number of man’s essential needs by facilitating the satisfaction of those which are, like alimentation, strictly necessary. The temperate zone of the north is the most favoured of all these. It contains nearly half the land surface of the globe. It is also the most populated, and the average density of population is far higher, for it contains about 1,207,000,000 inhabitants, or roughly speaking, three-quarters of the population of the globe. Here it is that we find massed the four great sources of the ancient and modern civilisation of the world, which also correspond to the four great groups of mankind; China with Japan; India, with the Deccan running down to the torrid zone; Europe, and the United States and Eastern Canada. In the three first centres the density of population is far greater than in any other large country. In the fourth, the number of human beings (some 94 millions) and the density are far less; but this centre has become one of the most important, by means of its activity of production. There remains the temperate zone of the south. In this zone, the ocean occupies relatively the largest space. The land emerges from it only at the termination of three continents——America, Africa, and Australia, terminated by Tasmania and New Zealand. Before the arrival of Europeans, each of these divisions was absolutely isolated, without any relations with the others, and inhabited by races entirely savage. The coming of the Europeans who peopled them, and the maritime commerce which ensued, have awakened them to civilisation. In the case of America, we have seen that free colonisation was not commenced until the nineteenth century. In Africa, at the opening of the nineteenth century, there were only a few ports occupied, and Australia was still practically untouched. To-day, in the temperate zone of the south, which comprises only a twelfth part of the land surface of the globe, there are 24 millions of inhabitants, nearly all civilised and of European descent. This population amounts to 1·5 per cent. of that of the globe; its density, therefore, is below the average.