bo IN STARRY REALMS. 



influence of the earth must have been experienced in these 

 primitive ages. 



We can hardly describe the tides in such a case 

 as producing actual currents like those which our sailors 

 know so well; they must rather be regarded as throb- 

 bings or heavings throughout the mass of the moon 

 which would originate deformations of its constitution. 

 Whenever movements of this kind are produced friction 

 must inevitably result, and it is characteristic of friction 

 to act in such a way as tends to check the movement by 

 which it is caused. The effect of the tides in the wholly 

 or partially fluid moon would therefore incessantly tend 

 to adjust the moon's movement in such a manner that the 

 tides should not further disturb it. There would, no 

 doubt, be a high tide on two opposite meridians of the 

 moon and low tide in the intermediate regions, but those 

 conditions would be permanent. To take the simplest 

 supposition we may regard the high tide as present on the 

 central meridian on that side of the moon turned towards 

 the earth, and as that side remains constantly directed to- 

 wards the earth during the moon's monthly movements, 

 the high tide remains always at the same lunar locality 

 There is no ebb and flow, there is no distraction of the 

 material of the globe, which, having become once adjusted 

 to this condition, remains without future tidal change. 



There cannot be a doubt that in ancient days when the 

 moon was sufficiently fluid, the action of the tides tended 

 without ceasing to the establishment of such an adjustment 

 between the rotation of the moon around its axis and the 

 revolution of the moon around the earth, that the two 

 should be brought to have equal periods. Friction would 



