284 PROCEEDINGS OF THE AMERICAN ACADEMY 



The light curves of four stars have been determined with sufficient 

 precision to permit a comparison with theory. All of these may be 

 represented by the formula Z'= 1 -f- m' sin (v' + a) -f- n' cos 2v', in 

 which L' is the light when the star has turned through the angle v'. 

 The difference between observation and theory amounts on the aver- 

 age to only about 0.03 of a magnitude. In other words, the light 

 of these stars at any time may be computed with this degree of 

 pi'ecision. 



Harvard College Observatoev, 

 Cambridge, U. S. 



