i8o EVOLUTION OF THE EARTH 



agree, and therefore must organize a well-regulated system of 

 government. The fact that in irrigated regions many peo- 

 ple live close together on a small area also tends to cause 

 society to be thoroughly and wisely organized. Moreover, 

 the mere fact that water is precious leads to economy in its use 

 and to intensive agriculture. Hence man's faculty for planning 

 and for devising new schemes to increase his crops is constantly 

 stimulated. The Hopis, whom we have already cited, are an 

 admirable example of this. Could there be any higher de- 

 velopment of agricultural science than their way of putting a 

 seed into the midst of a ball of wet clay and burying it in the 

 dry sand? The stalk of corn that grows from such a seed may 

 be only a foot or two high, but it bears an ear with a hundred 

 grains to replace the one grain that was planted. Irrigation, 

 it need hardly be said, is rarely practised in tropical countries. 

 So far as it exists there it is either a relatively late develop- 

 ment as in Java, or is confined to the highlands as in Peru, or 

 to certain dry regions as in India. Everywhere it is a direct 

 response to special types of climate. 



So it is with all agriculture. Its type depends upon the kind 

 of climate. After man has reached a fairly high stage of 

 culture the most stimulating of all kinds of agriculture appears 

 to be that which prevails in temperate regions where there is 

 rain at all seasons. There each farmer lives on his own inde- 

 pendent farm. He may not have the stimulus of close contact 

 with his neighbors which is found in irrigated subtropical 

 regions, but he has the great stimulus of being wholly inde- 

 pendent and of being constantly urged to meet his own needs. 

 Moreover, he must be industrious and alert to a degree de- 

 manded of no other kind of farmer. The constant variety of 

 weather to which he is subjected demands that he shall be 

 ready to cut or harvest his hay instantly when the right time 

 comes. He cannot put off cutting his grain as can the sub- 

 tropical farmer, for when once it is ripe the rain may come 



