6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 7 1 



sun plus sky, other curves are drawn showing the solar radiation as 

 measured on a horizontal surface. Then a curve is drawn of the 

 intensity of the solar radiation as measured on a surface at right 

 angles to the direction of the solar beam. The points of this curve 

 are obtained by dividing the solar intensity on a horizontal surface 

 by the sine of the angle of altitude of the sun, computed from the 

 hour angle, latitude, longitude and declination. (See figs. 1,2.) 



Following this are tables of the radiation measured during the 

 night preceding the eclipse and during the totality and a comparison 

 of these values. 



