6 CONTENTS. 



PART III. 



Page. 



Laws of temperature control of the geographic distribution of 



animals and plants 54 



Zone temperatures - 51 



The Boreal region . 54 



The Austral region 55 



The Tropical region 55 



PART IV. 



Crop tables 56 



Cereals 56 



Apples ... 57 



Apricots 62 



Cherries 62 



Grapes 64 



Peaches 65 



Pears 67 



Plums 68 



Strawberries 70 



Nuts 71 



Miscellaneous crops 73 



ILLUSTRATION. 



Map showing life zones of the United States Frontispiece. 



