96 



arise from the northerly movement of the ocean. Ice has been 

 seen floating in the southern hemisphere between latitudes 36° 

 and 39°. 



Having thus noticed the subject of temperature, it will be 

 proper to advert to the amount of moisture which the atmo- 

 sphere contains in different parts of the globe. In the tempe- 

 rate zone, with a mean temperature of 52j°, the annual evapo- 

 ration has been found to be between thirty-six and thirty-seven 

 inches. At Cumana, on the coast of South America (north lat. 

 10i°), with a mean temperature of 81*86 degrees, it was ascer- 

 tained to be more than 100 inches in the course of the year; at 

 Guadaloupe, in the West Indies, it has been observed to amount 

 to ninety-seven inches. The average yearly quantity of rain is 

 greatest within the tropics, and it seems to diminish the further 

 we recede from the equator. In general much more rain falls 

 in mountainous countries covered with extensive forests than in 

 those where wood is less abundant. The following shows the 

 quantity of rain fallen at Marmato, on the western Cordillera, 

 latitude 6° 28' north, elevation above the level of the sea 4836 

 feet, mean temperature about 68°, from the year 1833 to 1841 

 inclusive. 





1833. 



1834. 



1835. 



1836. 



1837. 



Jan, to March... 

 April to June... 

 July to Sept. ... 

 Oct. to Dec. ... 



Tns. 



15-15 



24-3 



20 



17-8 



Ins. 



5-15 

 29-6 

 12-9 

 24-12 



Ins. 

 25-14 

 34 6 

 21-2 

 36-14 



Ins. 



23-3 

 394 

 18-3 



28-10 



Ins. 



8-1 

 23-9 

 18-1 

 31-16 





59-6 



72-2 



127'16 



99-0 



81-7 







1838. 



1839. 



1840. 



1841. 



Jan. to March... 

 April to June... 

 July to Sept. ... 

 Oct. to Dec. ... 



Ins. 



21-10 

 41-18 

 19-0 

 31-0 



Ins. 



1016 



28-0 



23-16 



31-18 



Ins. 



18-3 



220 



93 



1417 



Ins. 



12-3 

 26-2 

 1635 

 32-2 





113-8 



9410 



64-3 



87-2 



It must not, however, be imagined that the climate of all hot 

 countries is characterized by such abundant rains ; for there 

 are many which from one year to another are either almost or 



