74 The Earth considered as a Planet. 



her workmanship. From a few simple 

 principles she produces the most aston- 

 ishing effects, and charms us no less by 

 the infinite diversity of her operations, 

 than by the skill and contrivance which 

 are manifested in the performance of 

 them. Of all the effects resulting from 

 her laws none is more simple nor more 

 pleasing to a philosophic mind than the 

 provision that is made for the alternate 

 succession of day and night, and the 

 regular return of the seasons. The phe- 

 nomena depend upon the most simple 

 and evident principle. We have the one 

 merely from the rotation of our globe on 

 its axis, and the other from the inclina- 

 of that axis to the plane of its orbit. 



The axis of the earth being inclined 

 23-| degrees to the plane of its orbit, 

 makes it, in moving round the sun, have 

 sometimes one of its poles and some- 

 times the other nearer that luminary. 



The absence of the sun's light pro- 

 duces a proportionable degree of cold ; 

 hence the seasons are, in the northern 

 and southern parts of the globe, distinctly 

 marked by different degrees of heat and 

 sold. It is this annual turning of the 



