1904.] On the Temperature Classification of Stars. 



233 



6. Description of the Photographs. 



Many of the photographs taken are too faint to reproduce well 

 enough to exhibit completely the striking differences shown between 

 the pairs of spectra. I shall therefore content myself by giving a 

 detailed description of each negative (Table II), only reproducing 

 those photographs which are sufficiently dense to plainly show the 

 phenomena under discussion. 



Table II. 



IS T o. of 

 negative. 



Date. 



Star. 



Stage of 

 tem- 



Type. 



Alti- 

 tude. 



Description. 







perature. 







From Stage 2 to Stage 4. 



19 



14 



37 



a Lyrae 



4 



Sir. 



5b' 



2 



Arct. 



57 



4 



Sir. 



59 



2 



Arct. 



58 



4 



Sir. 



42 



2 



Arct. 



39 



4 



Sir. 



68 



2 



Arct. 



68 



Faintly red, fairly 

 bright to Hy. 



Intense red, scarcely 

 extends beyond K. 



Red scarcely visible, 



maximum about 



A 4U0. 

 Fairly bright red, 



maximum about 



A 460. 



Red scarcely visible, 



maximum about 



A 418. 

 Fairly brigbt red, 



maximum about 



A 455. 



"Weak red, maxi- 

 mum about A 420. 



Very dense red ; 

 blue maximum 

 commences at F, 

 centre at A 460, 

 weak beyond 

 X 388. 



11 



28.1.03 



From Stage 4 to Stage 6. 



f /3 Orionis 



Canis Maj. 



Sir. 



21 Eed not so intense, 

 and ultra-violet 

 much more ex- 

 tended than in 



Sirius. 



22 Dense red, centre of 



maximum about i 

 ! A 422. 



VOL LXXIII. 



