JOURNAL OF THE COLLEGE OF SCIENCE, IMPERIAL UNIVERSITY, 

 TOKYO, JAPAN 



VOL. XXVII., ARTICLE 19. 



Studies on the Variables of the Algol-Type. 



By 

 Naozo Ichinohe, RigakusU. 



Lecturer in Astronomy, College of Science, Tokyo Imperial University. 



INTRODUCTION. 



The variation of light of ß Persei was found as early as in 

 1667 or 1669 by Montanari and it was confirmed by Maraldi 

 in 1694, as he sometimes assigned the third magnitude to this 

 star, while it was usually of the second magnitude ; and the year 

 1667 or 1669 is really the very beginning of this branch of 

 variables. But the law governing the peculiar change of light 

 remained unknown more than one century after the discovery. 

 At length, in 1782, Goodricke discovered that the variation of 

 light of this star was periodic, and the change took place only 

 in a small portion of the period, 9i hours, being constantly of 

 the second magnitude during the remaining time. Thus, we 

 may consider the year 1782 in which the law was discovered, as 

 the birth-day of this special kind of variable star. Then, a long 

 time went on without any addition of stars in this class of 

 variables till 1848, in which the similar characteristics of light- 

 change w^ere discovered in the stars S Cancri and ^ Tauri, re- 

 spectively by Hind and Baxendell (except £ Aurigae, which was 



