GRAVITATION. 



87 



guinea and feather so fixed at the top, that they can be 

 dropped by touching a wire. They go exactly together 

 to the bottom; which shows that the air is the only 

 cause why the feather usually falls more slowly. 



It will be very evident that the constitution of nature 

 might easily have been such, that some species of matter 

 would have been more strongly attracted than others. It 

 may be a subject of interesting reflection, to consider, 

 what would have been the effects of such an arrangement, 

 and by what phenomena such a fact would be made 

 manifest. 



3. It is the same at every distance. 



This statement will excite surprise also until it is ex- 

 plained. Let A be 

 any body of matter, ^-"""* 



and cde, and fgh, 

 represent concentric 

 spheres around it. 

 Now, what we mean 

 to say is, that the 

 force of attraction 

 which A exerts, at 

 the distance cde, 

 in every direction 

 from A, that is, in 

 the whole sphere, will 

 be tho same which 

 it will exert in the whole sphere at fgh. In other words, 

 the whole amount offeree exerted in every direction, by a 

 body, at any distance, is the same with the whole amount 

 in every direction, at any other distance. 



It will be evident from this principle, that, since the 

 whole amount is at every distance the same, and as the 

 sphere of influence increases the farther we go from the 

 body, the force at any one point must beless. In other 

 words, as the power of gravitation extends in every 

 direction, the farther we go from the body, it is, as it 

 were, diffused over a greater space, and consequently will 

 be, in any one point, weakened by this diffusion. For 



