second, this distance is found to agree very nearly 

 with what we should expect to find if the solar 

 attraction is sufficient to deflect the earth '119 of an 

 inch in the same time. Thus, in parts of an inch, 

 Mercury is deflected -792, Venus -227, Earth -119, 

 Mars -051, Jupiter -0044, Saturn -0013, Uranus 

 000323, and Neptune -000132. 



It is so likewise with the satellites of Jupiter, 

 Saturn, and Uranus ; for on taking any one of these, 

 and weighing the attractive powers of the primary 

 by the fall from the tangent of the orbit, and on 

 considering the diminution or augmentation of power 

 which must happen if these powers are inversely 

 proportional to the square of the distance, the spaces 

 through which the companion satellites are found to 

 fall in the same time are in exact accordance with 

 the requirements of the law. 



And not only does the sun attract the planet, and 

 the planet its satellite, according to the same law, 

 but the planets attract the sun and the satellites 

 their primaries in the very same manner. It ap- 

 pears, indeed, that every part of the solar system is 

 attracted by every other part with a force which is 

 inversely proportional to the square of the distance. 

 It would be easy to give many illustrations of this 

 great system, but the latest is the most conclusive 

 and triumphant, and we will content ourselves with 

 it, for if the law can be shown to hold good in such 

 a point, it may be assumed to be true in all points. 

 The illustration is this. The orbit of Uranus pre- 

 sented certain peculiarities, which could not be ac- 

 counted for by the gravity of the sun and the planets 



U 3 



