1904-5.] On Prof. Seeligers Theory of Temporary Stars. 513 
On Professor Seeliger’s Theory of Temporary Stars. 
By J. Halm, Ph.D., Lecturer on Astronomy in the Uni- 
versity of Edinburgh, and Assistant Astronomer at the Royal 
Observatory. 
(Read November 7, 1904. MS. received November 28, 1904.) 
Professor Becker’s paper “ On the Spectrum of Nova Persei and 
the Structure of its Bands,” recently published in the Transactions 
of this Society, contains an interesting confirmation of some results 
already pointed out by Messrs Campbell and Wright of the Lick 
Observatory,* which seem to he of considerable importance for the 
theory of temporary stars. By most careful micrometric measure- 
ments of the positions of the bright and dark hands in the photo- 
graphic spectrum of Nova Persei, Professor Becker arrives at the 
conclusion that all the hands are similar in type, and that the 
distances of corresponding maxima and minima from the centres 
of the hands are proportional to the wave-lengths. The results 
derived from the Lick photographs point to exactly the same 
conclusion. It appears, therefore, from these two carefully and 
independently executed series of observations, that the chemical 
nature of the elements, whose light-vibrations gave rise to the 
selective radiations and absorptions noticed in Nova Persei, had 
no influence on the appearance of the hands. According to the 
Lick observers, there is no evidence that the structure and char- 
acter of these hands were affected by other considerations than that 
of wave-length. 
This important result appears to necessitate now the exclusion 
from our view of those theories in which chemical or physical 
properties of the incandescent gases and vapours figure as deter- 
mining factors. It seems, for instance, incompatible with the high- 
pressure theory advocated by Professor Wilsing of Potsdam, because 
those effects of pressure on the displacements of spectral lines 
which form the basis of Wilsing’s theory are by no means the 
* Eighth Bulletin of the Lick Observatory. 
PROC. ROY. SOC. EDIN. — YOL. XXV. 
33 
