CLIMATE. 



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The Annual Mean Temperature not a Good Criterion. 

 Since one and the same figure may result equally from the 

 averaging of two widely divergent data, and from such as are 

 close together, it is clear that the mean annual temperature 

 cannot be a proper criterion of the agricultural adaptations of 

 a country. Thus an average temperature of 60 F. might re- 

 sult, equally, from the averaging of 65 and 55 degrees, or from 

 taking the mean of 15 and 105 degrees; yet the respective cul- 

 tural adaptations would be widely different. 



Extremes of Temperature arc Most Important. It is, on 

 the contrary, rather the extremes of temperature, more par- 

 ticularly of cold, but frequently also of heat, together with the 

 total amount of heat available during the growing season, 

 that determines such adaptation so far as temperature is con- 

 cerned; for no culture plant can be successfully grown where 

 the temperature during winter even occasionally falls for more 

 than a few hours below the point which it can resist; and for 

 each plant there is a certain aggregate requirement of heat to 

 carry it from germination to fruiting. Even different varie- 

 ties of one and the same plant differ materially in the latter 

 respect, so that it is very important that in the selection of 

 varieties to be grown, this factor should be taken into con- 

 sideration. It cannot be too strongly urged that the compari- 

 son of annual means of temperature, so commonly made by 

 promoters of colonization schemes, must not be taken as a 

 guide either in the estimate of cultures in which the immi- 

 grant may desire to engage, or by those in search of a climate 

 adapted to their health-conditions. 



Seasonal and Monthly Means. The statement of the mean 

 temperatures of the conventional four seasons spring, sum- 

 mer, autumn and winter afford a much clearer conception of 

 climatic adaptations ; provided always that the extreme tem- 

 peratures be considered at the same time. With the same un- 

 derstanding, the monthly means are still more instructive ; but 

 here again, it is most essential that the distribution and amount 

 of rainfall in each be regarded at the same time, since the most 

 desirable temperature is of no avail without the moisture re- 

 quired for vegetation. 



In some cases, e. g., that of California, it becomes neces- 

 sary for practical purposes to regard the " season," and not 



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