THE LIGHT OF THE STARS. 193 



equal to Algol, of the second magnitude. A 

 photograph by Williams at Brighton showed 

 that it must have been fainter than the twelfth 

 magnitude on February 20. On the evening 

 of February 23 the star was brighter than 

 Capella, and was then the brightest star in the 

 northern hemisphere. On February 25 it fell to 

 the first magnitude ; on March 1 to the second, 

 and on March 6 to the third. During the spring 

 and summer the light fluctuated considerably, 

 but in September and October faded to the 

 6*7 magnitude. In March 1902 it was of the 

 eighth magnitude, and in July 1903 of the 

 twelfth. 



The spectrum of Nova Persei was found by 

 Pickering to be of the Orion type on February 

 22 and 23. On February 24 the spectrum had 

 become one of the bright and dark lines, and 

 the hydrogen lines indicated a velocity of 700 

 to 1000 miles a second. Measures of the sodium 

 and calcium lines, by Campbell and others, in- 

 dicated a velocity of only three miles a second, 

 so that the displacements of the hydrogen lines 

 may have been due to an outburst of hydrogen 

 in the star. The spectrum was carefully studied 

 during the spring and summer by Pickering, 

 Lockyer, Huggins, Vogel, and others. On June 

 25 Pickering reported that the spectrum was 



N 



