OUR CHIEF TIMEPIECE LOSING TIME. 57 



would most of our readers learn if we were to tell them 

 that, " when the variability of the eccentricity is taken 

 into account, in integrating the differential equations 

 involved in the problem of the lunar motions that is, 

 when the eccentricity is made a function of the time 

 non-periodic or secular terms appear in the expres- 

 sion for the moon's mean motion " and so on ? Let it 

 suffice to say that Laplace had considered only the 

 effect of the sun in diminishing the earth's pull on the 

 moon, supposing that the slow variation in the sun's 

 direct influence on the moon's motion in her orbit must 

 be self-compensatory in long intervals of time. Adams 

 has shown, on the contrary, that when this variation 

 is closely examined, no such compensation is found to 

 take place ; and that the effect of this want of com- 

 pensation is to diminish by more than one-half the 

 effects due to the slow variation examined by Laplace. 

 These views gave rise at first to considerable con- 

 troversy. Pontecoulant characterized Adams's pro- 

 cesses as "analytical conjuring-tricks;" and Leverrier 

 stood up gallantly in defence of Laplace. The contest 

 swayed hither and thither for a while ; but gradually 

 the press of new arrivals on Adams's side began to 

 prevail. One by one, his antagonists gave way ; new 

 processes have confirmed his results, figure for figure ; 

 and no doubt now exists, in the mind of any astron- 

 omer competent to judge, of the correctness of Ad- 



