53 



thing, and becomes a mere point, when made use of to 

 measure the distance of the fixed stars. 



How great then must the real bulk of these luminous 

 spots be that are perceivable by us at such enormous 

 distance ! The sun is supposed about a million of times 

 greater than the earth, and a hundred and ten times 

 greater than all the planets put together. 



5. Whilst the planets perform these revolutions 

 round the sun, by which the course of their years is re- 

 gulated, they effect another amoug themselves, which 

 determines the alternatives of their days and nights. 



But how do these vast bodies remain suspended in 

 space ? What secret power retains them in their orbits 3 

 and enables them to circulate with so much regularity 

 and harmony] Gravity, that powerful agent, is the 

 universal principle of this equilibrium and these mo^ 

 tions : it penetrates into the inmost parts of all bodies . 

 By virtue of this force they tend towards each other in. a 

 proportion relative to their distance and bulk. So that 

 the planets tend towards the common centre of the 

 system, and they would be instantly precipitated into it, 

 if the Creator, when he formed them, had not endued 

 them with a centrifugal motion, by which they are 

 continually kept at a due distance from the centre. 

 Each planet, in constant subserviency to these two 

 forces, describes a curve in consequence thereof. By 

 this means the same force which determines the fall of 

 a stone, is the ruling principle of the heavenly motions : 

 wonderful mechanism ! whose simplicity and energy 

 give us unceasing tokens of the PROFOUND WISDOM of 

 its AUTHOR. 



The globe of earth, which is externally divided into 

 lands and seas, nearly level in their surfaces, is formed 

 within, at least to a certain depth, of leds of heteroge- 

 neous matter, that are almost parellel, more or less 

 dense, and of a finer or coarser texture. 



