19)4-5.] On Prof. Seeligers Theory of Temporary Stars. 531 
the band will somewhat resemble that given in fig. 8, the light 
being now distributed symmetrically to the normal position. The 
sequence of phenomena, as theory would require it, may therefore 
be described as follows. While the continuous spectrum was bril- 
liant, the observer must have noticed a strong displacement of the 
bright bands towards the red. We saw already that this conclusion 
is borne out by the observations (fig. 6). After the vanishing of 
the continuous spectrum, however, the same bands must have 
appeared shifted towards the violet, since then the maximum on 
which the observer would make his measurements, on account of 
the breadth and indistinctness of the band, lies on the violet side 
(fig. 7). The observer would therefore gain the impression that 
the star’s motion in the line of sight had been considerably 
changed during the interval between his two observations. 
This apparent shift towards the more refrangible side would 
gradually lessen, and finally the bright bands would appear in their 
normal positions (provided that the common motion of the whole 
system has been accounted for). Now, the student of the spectro- 
scopic evolution of Nova Aurigae will at once recognise an agreement 
between these theoretical conclusions and the facts actually observed. 
The agreement is sufficiently demonstrated by the following data. 
It is well known that the spectrum of Nova Aurigae during its last 
stages of luminosity, from August 1902 to the end of 1903, was 
almost purely gaseous, and resembled that of a planetary nebula. 
There is also the possibly strongest evidence that the hydrogen- 
lines were represented in this later spectrum as well as in that of 
the former period when continuous radiation was powerful. In 
the following table I give the measured wave-lengths of these lines 
in both cases,* and also their normal wave-lengths : — 
First Period (Feb. J 892). 
Continuous Spectrum, 
strong. 
Two Maxima in 
bright H-bands. 
H/3 
4869-9 ) 
4861-6 ( 
Hy 
4347'8 1 
4340-6 j 
HS 
4108 ( 
4102 ( 
Second Period (Aug. 1892). 
Continuous Spectrum, 
feeble or absent (?). 
Maxima of 
bright H-bands. 
4857 
Normal wave-length 
of H-lines. 
486T5 
4336 
4098 
4340-6 
4101-9 
Of. Scheiner-Frost, pp. 287 and 291. 
