Climate 181 



which we do not think of protecting, are matted up 

 like mummies for the winter. 



Then again, myrtles will flourish out of doors all the 

 year round in Ireland, as well as they do in Portugal ; 

 but plums and pears do not usually ripen well, though 

 they will do so perfectly on the continent, in the same 

 latitude. 



It is evident, therefore, that the climate of a country 

 does not depend solely upon its position with regard 

 to the equator. Indeed, the great characteristic of the 

 equatorial climate is, not so much its heat, as its 

 wonderful uniformity. Hot it is, of course, though 

 not as hot as the plains of North India ; but there is 

 nothing to be called change of season, and there is 

 seldom more than 16 or 17 of difference between day 

 and night. It is not often that the thermometer stands 

 above 90 or 91 F. by day, or falls below 74 F. by 

 night. And the temperature of the soil varies but 

 little, too. Four or five feet below the surface it never 

 varies at all, and remains constantly at 80 F., just 

 about half-way between the temperature of night and 

 day. 



Where the temperature of the air varies more, there 

 the temperature of the soil varies more also, and to a 

 greater depth. At the equator, the sun affects only 

 the upper four or five feet of the soil, the change 

 between day and night being unfelt below this ; but in 

 England the change between summer and winter is 

 felt to a depth of fifty or sixty feet probably ; and below 

 this the temperature remains steady at but a little 

 above 40 F. 



40 F. is about the mean temperature of the air in 

 England, a.s 80 F. is that of the equatorial region 



