Sxcr. XXXVII. DISAPPEARANCE OP STARS 363 



to us to be 3-7 times as large as the sun, and would give 

 13-8 times more light. Many of the fixed stars must be 

 infinitely larger than Sirius. 



Many stars have vanished from the heavens; the 

 star 42 Virginfs seems to be of this number, having been 

 missed by Sir John Herschel on the 9th of May, 1828, 

 and not again found, though he frequently had occasion 

 to observe that part of the heavens. Sometimes stars 

 have all at once appeared, shone with a bright light, 

 and vanished. Several instances of these temporary 

 stars are on record ; a remarkable instance occurred in 

 the year 125, which is said to have induced Hipparchus 

 to form the first catalogue of stars. Another star ap- 

 peared suddenly near a Aquilae in the year 389, which 

 vanished, after remaining for three weeks as bright as 

 Venus. On the 10th of October, 1604, a brilliant star 

 burst forth in the constellation of Serpentarius, which 

 continued visible for a year; and a more recent case 

 occurred in the year 1670, when a new star was discov- 

 ered in the head of the Swan, which, after becoming 

 invisible, reappeared, and having undergone many varia- 

 tions in light, vanished after two years, and has never 

 since been seen. In 1572 a star was discovered in Cas- 

 siopeia, which rapidly increased in brightness till it even 

 surpassed that of Jupiter ; it then gradually diminished 

 in splendor, and having exhibited all the variety of tints 

 that indicate the changes of combustion, vanished sixteen 

 months after its discovery, without altering its position. 

 It is impossible to imagine anything more tremendous 

 than a conflagration that could be visible at such a dis- 

 tance. It is however suspected that this star may be 

 periodical, and identical with the stars which appeared 

 in the years 945 and 1264. There are probably many 

 stars which alternately vanish and reappear among the 

 innumerable multitudes that spangle the heavens ; the 

 periods of several have already been pretty well ascer- 

 tained. Of these the most remarkable is the star Omi- 

 cron, in the constellation Cetus. It appears about twelve 

 times in eleven years, and is of variable brightness, some- 

 times appearing like a star of the second magnitude ; 

 but it does not always attain the same lustre, nor does 

 it increase or diminish by the same degrees. Accord- 



