40 



THE TIDAL PROBLEM. 



Relative to the question whether the lost energy, in the present con- 

 figuration of the earth-moon system, must come wholly from the rotation 

 of the earth or in part from the revolution of the moon, Dr. Moulton finds 



Fig. 5. 



that the loss would be derived partitively in the ratio of 27.3 from the 

 rotation of the earth to 1 from the revolution of the moon.^ 



* The eeneral relations here involved are shown grapliically by Sir George Darwin 

 in Thomson and Tait's Nat. Phil., II, p. 511. These are developed in much detail and with 

 many applications in the paper of Dr. Moulton in this series, some of the details and appU- 



