61 



for example, is only about 76 degrees, while that 

 of the human body is 98 degrees ; and, as heat 

 always tends towards an equilibrium, it is obvious 

 that, as its general course, in this place, is from 

 the body to the atmosphere, such a surface as 

 favours its radiation will be a means of keeping 

 the body comfortably cool. 



And what, too, do we not owe to the irregula- 

 rities of the earth's surface, the lofty mountains 

 and the sloping vallies ? Imagine the sameness, 

 and the dullness, and the want of interest that 

 would have accompanied a still and level flat, 

 had it existed in place of the beautiful undulat- 

 ing valley, the abrupt and rocky precipice, the 

 extended plain, the distant and majestic moun- 

 tain. Had such a disposition been the case, 

 whence would have come our constant and in- 

 dispensible supply of spring water ? The little 

 rain that fell would speedily have found its way 

 back to its mother ocean, leaving us little better 

 off than the wanderer among the arid deserts of 

 Arabia, unprovided for, and perishing from thirst 

 and want of almost every kind. All the springs 

 and wells in the world consist merely of rain 

 water which has sunk into the bowels of the 

 earth, again appearing, or gradually escaping, at 

 lower places ; and it is to the irregularity of the 

 mountains, and to the porous and rocky caverns 

 of the earth, that we are indebted for the faci- 

 lity with which water passes upwards and down- 

 wards through their various curvatures and levels. 

 After wandering long, and filtering through soils 



