Alt. S.— Y. Takaliashj 



Tahli- t. 



Actual v^alues of 



oh 



for iron lines were obtained by interpo- 



lation, and, if desired we can get the wave lengtli intervals by 

 multiplying hy )^\ tbis is unnecessary, as it is more rational to 

 express the Zeeman separation in cbange of frequenc^T^ tban in 

 wave length. 



Tbe cbief advantage of using tiie echelon spcctri_>scope 

 consists in its higb resolving power, tbe great intensity of bglit 



and the comparatively large vahie of - ^ ^^ '' . Tbe first allows 

 us to observe fine separations in weak fields, tbe second is 

 convenient especially in investigations witb strong fields, and tbe 

 last is important in tbe investigation of spark spectra, for tbe 

 lines in such spectra bave considerable widtlis. l''a])ry-Perot"s 

 mterfero meter and hummer Gebrcke's ])!ate satisfy tbe first and 

 the second, but not tbe tbird condition. Kven witb tbe ecbelon 

 gratmg - — ^^ — is not sufiiciently large to enable us to measure 

 the separation in some fields wben one component falls npon or 

 close by the otber. Complex separations giving moie tban foui" 



