DOUBLE STARS 



159 



by the transit of a dark sphere across the face of a bright 

 one. The result of this investigation, which, although it 

 involves laborious calculation, presents no real difficulty, 

 was that, upon assuming certain relative proportions for 

 the star and companion and their distance apart, as well 

 as for the inclination of the orbit to the line of sight, a 

 theoretical light curve was obtained that practically 



Moor* iO 



FIG. 9. Light curve of Algol. 



coincided with the one deduced from observation. The 

 actual assumptions necessary for this agreement were 

 that, taking the radius of Algol as unity, that of the com- 

 panion is represented by 0-764 and the distance between 

 their centres is 4-33. Further the plane of the orbit 

 makes an angle of 3 with the line of sight. The system 

 is represented to scale in fig. 10, and the view of it as it 



