0. T. Sherman — Spectrum of Nova Andromedoz. 379 



precaution in observing, the eye was used only after some 

 hours sleep, the spectrum was gazed at intently for some mo- 

 ments and subjected to a slight apparent to-and-fro motion. 

 No light more brilliant than the first glare of a match was 

 used. The spectroscope was a direct vision by Duboscq, pro- 

 vided with two series of prisms. Using the single series, b % and 

 5 4 are just separated, using the double series the nickel line 

 between the I) 1 and D a and the fine lines between b t and b 2 are 

 visible. The single series was usually employed for work, 

 the double as a check. 



On the earliest opportunity after receiving the information, 

 namely the early morning of September 5th, the telescope was 

 directed to the Nova. On the whitish blue stripe forming the 

 continuous spectrum were discerned one bright line crossing 

 the spe3trum and farther toward the red two bright knots of 

 light. They were not very much brighter than the surrounding 

 glare but were evident. They remained when the larger 

 dispersion was employed. 



Settings were made by bringing the cross wire appearing as 

 a dark line upon the bright background over the apparent con- 

 densation. The scale was read by the glare of a match and the 

 observation recorded by a pencil dot upon a prepared form. 

 The instrument was then pointed to the comparison star, say 

 y Cassiopeise and a similar observation made. This process was 

 repeated independently upon Sept. 5, 7, 9, 11. On Sept. 16 

 and 21 the lines were seen but no setting attempted. Since 

 then no observations upon the Nova have been obtained. The 

 mean of the settings upon the three stars gives the following 

 series : 



7 Cass. (3 Lyree. Nova Androm. 



H a 20°-2 20°-32 



D 3 19-35 19-44 



? 19-10 19-03 18-98 



? 18T» 18-43 18-51 



H/3 17-56 17-51 17-55 



Ho 15-93 15-90 



H 7 ? 14-20 14-25 



The lines Ha D3 H/3 B.6 have been identified by other ob- 

 servers. On their foundation the curve connecting the scale 

 readings and wave lengths was drawn. The equivalents of the 

 scale readings read off are: 



From y Cass. From (3 Lyrse. Mean. 



18-51 = 536-0 527-0 531-5 



18-98 = 564-0 551-0 557'5 



The remaining line, H/3 seems from its image to be due to 

 the light of the whole nebula. The two 18'51 and 18*98 seem 

 to be due to the light of the Nova. 



