Lesson vu] THE EARTH. 27 



" God to men than the latter. And as the ma- 

 " thematician would be judged to wander out of 

 " his province, if he should pretend to controvert, 

 " or set aside any article of faith from principles 

 " of geometry ; so it must be granted, the divines 

 ft are no less out of their limits, when they ven- 

 " lure to pronounce on a point of natural know- 

 *' ledge, beyond the reach of any ftot versed in 

 " geometry and optics, merely from holy Scrip- 

 " ture, which does not pretend to teach any thing 

 " of the matter." 



I shall now proceed to exhibit to you the Earth 

 in an astronomical point of view; for I am con- 

 vinced, that the more attentively you consider it in 

 this light, the more willingly you will throw aside 

 the common prejudices, and place the true result 

 of philosophical reasoning in their stead. 



The earth, considered as an element, after the 

 manner of Aristotle, is called Terra: but amongst 

 astronomers it has obtained the name Tellus, and 

 is denoted by the character ; it is the third pla- 

 net from the Sun, its mean distance from him 

 being 95 millions of miles; and its diameter is 

 found to be 7970 miles*. It is nearly 365| days in 

 completing a revolution through its orbit, 

 is the length of our year : and a complete rof 

 upon its axis is performed in the compass of a : na- 



* Strictly speaking, the Earth, and indeed all toe planets 

 are spheroids formed by the rotation of ellipses of small 

 ellrpticity upon their minor axes ; but their deviation from 

 the spherical form is too minute to need any particular spe- 

 cification in a populai work like this. 



"e 2 tural 



