690 
DR. W. HUGGINS ON THE PHOTOGRAPHIC SPECTRA OP STARS. 
stages of their life changes through which they pass is a point on which we know 
nothing certainly. On this hypothesis the stars which have been observed would have 
to be arranged approximately in the following order :—* 
Sirius. Vega. 
r) Ursse Majoris. 
a Yirginis. 
a Aquike. 
Rigel. 
a Cygni, 
Capella. The Sun. 
Arcturus. 
Aldebaran. 
Betelgeux ? 
* According to the reasoning of Mr. Johnstone Stoney, the changes of the stars in time would be in 
the inverse order of the arrangement I have suggested in the text. (See Proc. Roy. Soc., vol. xvii., 
pp. 47-51.) 
