CLIMATE AND AGRICULTURE 47 



It is the uniform temperature, not a high one, which 

 characterizes lands close to the equator. The average 

 yearly temperature is greater 15 north, about the lati- 

 tude of Manila, where it is 26.3, than on the equator 

 itself, where it is 25.9. It must be because the tem- 

 perature is not sufficiently uniform, that some plants, 

 such as the mangosteen and durian, which are usually 

 regarded as the two most delicious tropical fruits, do 

 not grow as far north as Panay. Islands have usually a 

 more uniform temperature than continental places. 



The average temperature for a month is found by add- 

 ing the temperatures of all the days, and dividing the sum 

 by the number of days. 



Advantages of the Tropics. No plant of agricultural 

 value can grow and produce crops near the freezing 

 point of water (o), and many of them are killed by 

 frost. For this reason, crops do not grow during the 

 winter, where there is a winter; and there are only about 

 four months during which the plants of temperate coun- 

 tries grow really actively. 1'Yosts probably never occur 

 in the Philippines except in the high mountains of 

 northern Luzon. So far as the temperature is con- 

 cerned, it should be possible to raise in the Philippines 

 two or more crops in a year, of most plants of temperate 

 lands. 



Light. The advantage of tropical countries in agricul- 

 ture is even greater than the temperature shows; for 

 they also receive more light, and so plants can form 

 more organic food. The light at Para, in Brazil, and at 



