100 NOMOS. 



is the space through which the moon ought to fall, 

 and does fall, in the same time. This, then, is a 

 strong argument that the same force of gravity acts 

 upon the moon and upon the stone. 



On inquiry further, it is found that the earth is 

 deflected from the tangent of her orbit 0*1 19 of an 

 inch in the second, and hence it follows that the 

 attraction of the sun for the earth must be no less 

 than 354,936 times greater than the attraction which 

 operates at the surface of the earth, if this attraction 

 increases after the same ratio as the distance dimi- 

 nishes. At the surface of the earth a stone gravitates 

 through 193 inches in the first second; at the sur- 

 face of the sun it would gravitate through 5514 

 inches. This disproportion is indeed great, but it is 

 not greater than may be supposed to exist if the 

 sun's powers of attraction are in any degree propor- 

 tionate to his volume a volume so vast, that (to 

 use Sir John Herschel's illustration) the surface of 

 the sun would extend as much beyond the orbit of 

 the moon as that orbit is beyond the surface of the 

 earth if the centre of the sun was where the centre 

 of the earth is at present. If, indeed, the solar 

 powers of attraction were directly proportionate to 

 the solar volume, they would be four times greater 

 than they are ; but, as they are, comparing volume 

 with volume, they are four times less than the 

 powers of terrestrial gravity. 



The attraction which acts upon the other planets 

 is inversely proportional to the square of the dis- 

 tance ; for on measuring the distance to which they 

 are deflected from the tangents of their orbits in a 



