6i 



FIG. 46. Milky Way, showing Nebula surrounding p Ophiuchi. 



particles more than the red light. For the same 

 reason the very distant stars should appear redder 

 than the nearer ones, if there is similar scattering 

 in space. It is therefore necessary to determine, 

 by several independent methods, the proportion 

 of red and blue light sent us by near and distant 

 stars. 



THE BRIGHTNESS OF THE STARS. 



A knowledge of the relative intensity of the light 

 of the different stars, from brightest to faintest, 

 is essential in statistical investigations of their 

 distances, luminosities, and distribution in space. 



