54 



INFLUENCE OF A MAGNETIC FIELD UPON THE SPARK SPECTRA OF IRON AND TITANIUM 



of the separations for the -components range from the values of 2a to :^a and that the various values 

 of the multiples of the interval are more or less uniformly distributed throughout the spectrum. This 

 was shown for the triplets (p. 47), the greater number of which show a separation greater than 2a. The 

 exceptional large and small values for triplets, together with the mean separations of the complex lines, 

 combine to form a fairly definite mean which holds for the whole range of spectrum examined. 



Since AK/\- is sJwun to be very nearly constant, it may be said that for iJie spectra of iron and titanium, and 

 probably for spectra in general, the mean separation oj the n-components varies as the square of the wave-length. 



A similar rule must hold for the /^-components, since it was shown (pp. 48-49) that complex lines of 

 the same structure in different parts of the spectrum show the same relation to the interval a. 



It is of interest to note that a computation along the hues of that carried out here, but different in 

 method and with comparatively Httle material at disposal, was made by Mr. Hale (38) in his comparison 

 of sun-spot doublets with the Zeeman separations on some prehminary plates made by the author. The 

 mean AX for a number of iron lines in the blue was divided by the square of the mean wave-length for 

 the region considered. Measurements for lines extending from the green into the red were treated simi- 

 larly. The quotients of the mean AX by the square of the mean X for the two regions agreed exactly. 

 While this result does not have the same significance as the comparison of the mean values of AX/X-, it 

 is clearly based on the same relation for the rate of increase of AX with X. 



THE EFFECT OF THE MAGNETIC FIELD UPON ENHANCED LINES. 



In my former paper (51) on the titanium spectrum, the behavior of the enhanced hnes was examined 

 to see if, as a class, they were affected by the magnetic field differently from the non-enhanced lines. 

 The various types of separation were found to occur in about the same proportion for the enhanced hnes 

 as for the spectrum in general. The same conclusion was arrived at by Mr. Babcock (62) for the enhanced 

 lines of chromium and of vanadium. 



Table 8 gives the numbers of enhanced and non-enhanced lines considered both as to type and magni- 

 tude of separation. Here, as in Table 3, a given type includes both the clear and the questioned cases for 

 that type occurring in Tables i and 2. 



Table 8. Comparison or Types of Separation for Enhanced 

 AND Non-Enhanced Lines. 



The enhanced hnes of each element are found to present a diversity of types. The enhanced and 

 non-enhanced triplets are in about the same ratio as the total number of enhanced and non-enhanced 

 lines, both for iron and titanium, this ratio being about 1:14 for iron and about 1:5 for titanium. Those 

 types for which the number is suflicient to give the comparison some weight are in the same ratios. There 

 seems to be no undue proportion of any one type among the enhanced lines, considered as a whole. 



