ABSTRACT
IN the preceding chapters there have been illustrated many examples of topographic control of the sites of villages, towns, and cities; but so far no special attention has been given to this factor in the broadest sense. It is quite obvious that in general the cities of the world are most commonly found on low-lying plains, where agriculture is widespread and communications are easy. Temperature, however, alters rapidly with elevation, at the rate of about i° F. for each 300 feet of ascent. Since most folk like a temperature around 65 ° F. it is clear that the optimum lies at different levels in different latitudes. This is suggested in the graph given in Fig. 91. At sea level cities in latitude 350 N. are favoured with the best climate, since the average here is 65 ° F. If one lives in latitudes warmer than this, it is well to live at higher elevations as suggested in the graph. At the Equator, where the sea-level temperature is about 80° F. it is necessary to climb 4,500 feet to reach the elevation where 65 ° is the average. The graph suggests (at B, C, D and E) the heights of the mountains which give optimum climates.
