176 TABLE 154. 



WAVE-LENGTHS OF FRAUNHOFER LINES. 



For convenience of reference the values of the wave-lengths corresponding to the Fraunhofer 

 lines usually designated by the letters in the column headed " index letters," are here tabulated 

 separately. The values are in ten millionths of a millimetre, on the supposition that the D line 

 value is 5896.155. The table is for the most part taken from Rowland's table of standard wave- 

 lengths. 



* The two lines here given for A are stated by Rowland to be : the first, a line " beginning at the head of A, out- 

 side edge ; " the second, a " single line beginning at the tail of A." 

 t The principal line in the head of B. 



Chief line in the a group. 



See Table 152, Rowland's Solar Wave-lengths (foot of page) for correction to reduce these values to Fabry-Buisson 

 system of wave-lengths. 



SMITHSONIAN TABLES. 



