It has been observed, with much truth, that the early civiHzation of mankind was detennined by natural causes, or, in other words, by the fertilizing power of great rivers and by the influence of a warm and genial climate, conducive alike to the production of crops and to the comfort of man. Other causes have exerted a greater influence in more modern times, and a temperate or cold climate has fostered the more robust civilization of these days ; but in the remote past we shall seek in vain for the first glimpses of human civilization except on favoured spots, where Nature helped man by copious and fertilizing inundations, and a wami and genial climate.
