272 TABLE 321. 



STANDARD SOLAR WAVE-LENGTHS. ROWLAND'S VALUES. 



Wave-lengths are in Angstrom units (io~ 7 mm.), in air at 20 C and 76 cm. of mercury pressure. 

 The intensities run from I, just clearly visible on the map, to 1000 for the H and K lines; below 

 I in order of faintness to oooo as the lines are more and more difficult to see. This table contains 

 only the lines above 5. 



N indicates a line not clearly defined, probably an undissolved multiple line ; s, a faded appear- 

 ing line; d, a double. In the "substance" column, where two or more elements are given, the 

 line is compound ; the order in which they are given indicates the portion of the line due to each 

 element ; when the solar line is too strong to be due wholly to the element given, it is represented, 

 Fe, for example; when commas separate the elements instead of a dash, the metallic lines coin- 

 cide with the same part of the solar line, Fe, Cr, for example. 



Capital letters next the wave-length numbers are the ordinary designations of the lines. A indi- 

 cates atmospheric lines, (wv), due to water vapor, (O), due to Oxygen. 



Corrections to reduce Rowland's wave-lengths to standards of Table 314 (the accepted standards, 1913). Temperature 

 15 C, pressure 760 mm. 



" The differences "(Fabry-Buisson-arc-iron) (Rowland-solar-iron)" lines were plotted, a smooth curve drawn, and 

 the following values obtained : 



Wave-length 3000. 3100. 3200. 3300. 3400. 3500. 3600. 3700. 



Correction .106 .115 .124 .137 .148 .154 .155 .140 



H. A. Rowland, " A preliminary table of solar-spectrum wave-lengths," Astrophysical Journal, 1-6, 1895-1897. 

 SMITHSONIAN TABLES. 



