73 



calculate its distance. If this method proves to 

 be generally applicable it will give a means of 

 finding the distances of stars too remote to be 

 measured by other means. From a physical point 

 of view it is also of value, because of its bearing on 

 the constitution of stellar atmospheres. 



FIG. .51. Dome of 6o-inch Reflector. 

 OTHER RESEARCHES IN PROGRESS. 



A detailed account of the investigations made 

 or in progress would include many additional sub- 

 jects, such as the measurement of the brightness 

 of the night sky, the study of the spectra of 

 nebulae, star clusters, the Zodiacal Light, and the 

 Milky Way, the determination of standards of 

 wave-length for the use of spectroscopists, the 



