ON GEOLOGICAL TIME. 29 



trary, the combined influence of the greater 

 attraction on the nearer protuberance of the 

 waters (H), and of the less attraction on the 

 more remote protuberance (H') would, if the 

 whole were rigid, tend to turn the line H'H 

 towards the direction OM. If the round earth 

 rotated inside the waters, these not sharing its 

 rotation, the effect would be as if a mechanical 

 friction strap or belt were applied round the 

 earth's equator, and were held from turning by a 

 couple of forces equal in moment (or rotational im- 

 portance) to that calculated as what is technically 

 called "the moment round the earth's axis" of 

 the moon's attraction on the two protuberances. 

 12. But the waters do not get pulled back by 

 the moon as a whole. They are, as a whole, 

 drawn along with the solid earth by friction on 

 the bottom, and by friction of water on water. 

 Therefore, from century to century, the water 

 moves along with the earth. Though it is due, 

 in the first place, to a force in the water, the 

 resultant effect on the earth and the water is the 

 same as if the whole were a solid globe rotating 



