528 Proceedings of Royal Society of Edinburgh. [sees. 
Aurigae. Afterwards I shall have occasion to exhibit other curves 
representative of the conditions present in Nova Persei, and I shall 
then be in a position to show how the observed differences in the 
character of the bands of these two stars can be accounted for. 
Fixing our attention for the present on fig. 6, we notice a broad 
bright band strongly displaced towards the red, and a broad diffuse 
absorption-band considerably shifted towards the violet. A re- 
markable feature is the distinct appearance of seeming 4 reversals ’ 
in both the emission- and absorption-bands. Now, this same 
phenomenon was noticed in the observed spectrum. I may quote 
the following remark from Scheiner-Frost’s Astronomical Spec- 
troscopy , pp. 288—9 : — “ The microscopical examination of the 
photographic spectra showed the individual lines, both, dark 
and bright, to be quite complex. A fine bright line could be seen 
extending down through the middle of many of the dark lines, 
and many of the bright lines had two or more points of maximum 
intensity From measurements on nine plates obtained 
at Potsdam between 14th February and 4th March (1892) Vogel 
deduces the following results, to which are added those calculated 
by Vogel from Campbell’s measurements on six plates taken between 
8th February and 6th March, and those published by Belopolsky from 
measurements on six plates taken from 24th February to 3rd March 
1892. The velocities have been corrected for the motion of the 
earth, and are therefore relative to the sun. A + velocity denotes 
recession from the sun, a - velocity approach toward the sun. 
Displacements in Tenth- Metres. 
Line employed. 
Bright line 
within dark. 
First Max. 
of intensity. 
Second Max. 
of intensity. 
Third Max. 
of intensity. 
h 7 
-10*3 
-o-i 
+ 8*2 
H5 
- 9-3 
-0-8 
' +5-4 
H 
-io-i 
-2*1 
+ 3'5 
K 
- 9’4 
-1*7 
+ 3-3 
Vogel Mean 
- 9-8 
-1-2 
+ 5-1 
F 
- 10-4 
+ 8-3 
n 7 
- 9-3 
+ 7*2 
+ 14-4 
H5 
- 7' 
+ 6’ 
Campbell Mean 
- 8-9 
+ 7-2 
Belopolsky H 7 
- 9*8 
-0-7 
+ 8-6 
+ 157 
