DIAGRAM TO I LLTSTR ATK AI.IIA/KX S M K ASl'RKMKNT OF THIi 

 HEIGHT OF THE ATMOSPHERE 



(For explanation sec page K>. It will be understood, of course, that the dis- 

 torted proportions make an angle very inaccurate. HMS, for example, as shown 

 in the diagram, is obviously much greater than IQ. Perhaps it should be added 

 that the angle HMS would not at all serve the purpose to which it is here put were 

 it not that the distance of the sun makes the ray SM virtually parallel to the im- 

 aginary line SA, which latter defines the actual angle of the sun's position with re- 

 gard to the observer at A). 



