6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 66 



" The values in the table just given are a standard of reference, and 

 the values obtained at these wave lengths on any da'y of observation 

 are comparable with them as soon as reduced to the form given in the 

 next to the last line of table 53. 



MEAN DISTRIBUTION OF RADIATION ALONG THE SOLAR 

 RADIUS FOR DIFFERENT WAVE LENGTHS 



" The following tabular summary of the distribution of brightness 

 of different wave lengths along the diameter of the sun's disk has 

 been obtained in the manner just described from numerous observa- 

 tions made between November i, 1906, and January i, 1908. Profs. 

 Schwartzchild and Villager determined the distribution of radiation 

 along the diameter of the sun for the very short wave length, 

 A = o.323/x, by photographic observations made after silvering the 

 objective of their telescope.' In this way they observed only with 

 the ultra-violet rays transmissible by silver. The following table 

 includes the mean of observations of Schwartzchild and Villager: 



Table (55) 3. — Mean distribution of radiation along radius of solar disk 



[Intensity at center as unit.] 



We now give the mean distribution of radiation along the solar 

 radius for different wave lengths as found by the observations of 

 191 3. The tables here given are conformable to tables 54 and 55 of 

 Vol. 3 of the Annals. They relate, however, to other wave lengths. 



^ Astrophysical Journal, Vol. 23, pp. 284 to 305, 1906. 



