OF THE HEAVENS AND THE EARTH. 279 



earth may be compared to a great magnet, rolled in UECT. 

 filings of steel, which attracts and keeps them equally ^^^ 

 fast to its surface on all sides. Hence, as all terrestrial 

 bodies are attracted towards the earth's center, they 

 can be in no danger of falling from any one side of the 

 earth, more than another. 7 * 



The heaven or sky surrounds the whole earth : and Up and 

 when we speak of up or down, we mean only with re- wnat ' 

 gard to ourselves ; for no point, either in the heaven or 

 on the surface of the earth, is above or below, but only 

 with respect to ourselves. And let us be upon what 

 part of the earth we will, we stand with our feet to- 

 wards its center, and our heads towards the sky : and 

 so we say, it is up towards the sky, and down towards 

 the center of the earth. 



To an observer placed any where in the indefinite All object* 

 space, where there is nothing to limit his view, all re- " nsV*!*" 

 mote objects appear equally distant from him ; and pear 

 seem to be placed in a vast concave sphere, of which diataut. 

 his eye is the center. Every astronomer can demon- 

 strate, that the moon is much nearer to us than the sun 

 is ; that some of the planets are sometimes nearer to 

 us, and sometimes farther from us, than the sun ; that 

 others of them never come so near us as the sun always 

 is; that the remotest planet in our system is beyond 

 comparison nearer to us than any of the fixed stars are ; 

 and that it is highly probable some stars are, in a man- 

 ner, infinitely more distant from us than others. And 

 yet all these celestial objects appear equally distant 

 from us. Therefore, if we imagine a large hollow sphere O f the*" 



of glass to have as many bright studs fixed to its in- heaven 



- , . .. , . and earth 



side as there are stars visible in the heavens, and these represent- 

 ed in a 

 machine. 

 Note 73. A reference to this fact will shew that two pendulums 



or plumb-lines suspended freely on the earth's surface, would not hang 

 parallel to each other, but assume such a direction as would bring 

 them in contact at the center of gravity of the globe. 



