At the risk of being prosy, I will mention the _a priori_ grounds upon which we may argue that the civilization of Central America did not grow up there, but was brought ready-made by a people who emigrated there from some other country. There is a theory afloat, that it is only in temperate climates that barbarous nations make much progress in civilizing themselves. In tropical countries the intensity of the heat makes man little disposed for exertion, and the luxuriance of the vegetation supplies him with the little he requires. In such climates—say the advocates of this theory—man acknowledges the supremacy of nature over himself, and gives up the attempt to shape her to his own purposes; and thus, in these countries, the inhabitants go on from generation to generation, lazily enjoying their existence, making no effort, and indeed feeling no desire to raise themselves in the social scale. Upon this theory, therefore, when we find a high civilization in hot countries, as in the plains of India, we have to account for it by supposing an immigration of races bringing their civilization with them from more temperate climates. This theory of civilization favours the idea of the Central American cities having been built by a people from Mexico. The climate of the Mexican highlands, which may be taken in a rough way to correspond with that of North Italy, is well suited to a nation’s development. But the cities of Yucatan and Chiapas, though geographically not far removed from the Mexican plateau, are brought by their small elevation above the sea into a very different climate. They are in the land of tropical heat and the rankest vegetation, in the midst of dense forests where pestilential fevers and overwhelming lassitude make it almost impossible for Europeans to live, and where the Indians who still inhabit the neighbourhood of the ruined cities are the merest savages sunk in the lowest depths of lazy ignorance. If this climate-theory of progress have any truth in it, no barbarous tribe could have raised itself in such a country to the social state which is indicated by the ruins of such temples and cities. They must have been settlers from some more temperate region. While wandering about the hill of Xochicalco we came upon a spot that strongly excited our curiosity. It was simply a small paved oval space with a little altar at one end, and, lying round about it, some fragments of what seemed to have been a hideous grotesque idol of baked clay. Perhaps it was a shrine dedicated to one of the inferior deities, such as often surrounded the greater temples; for, in Mexico, astronomy, astrology, and religion had become mixed up together, as they have been in other quarters of the globe, and even the astronomical signs of days and months had temples of their own.