CASES OF DISSYMMETRY. 



There are but few striking examples of dissymmetry in the iron and titanium spectra, either in spacing 

 of the components or in the intensities of the violet and red components. However, fourteen lines show- 

 ing distinct dissymmetry may be listed as shown herewith: 



The nature of the dissymmetry is covered in each case in the 

 "Remarks" column. Several triplets show either the red or the violet 

 component decidedly stronger. Quintuplets are hkely to show irregular 

 spacing or intensity, or both, as in the cases of XX3718.554, 3760.679 and 

 5455.834, of iron. The last hne has its central w-component moved dis- 

 tinctly to the red from the position of the no-field line (see Plate IV). 

 The titanium septuplet X 4298.828 shows three ^-components, the interval 

 between the central and violet components being about two-thirds that 



between the central and red. This line appears on Plate V. Several of the other lines are of complex 

 type and highly unsymmetrical. 



The plates taken in this investigation are for the most part not suitable for the detection of a differ- 

 ence in the spacing from the central line of the violet and red component of triplets, since a Nicol was 

 almost always used to separate the n- and />-components. However, two of the best plates in the set 

 were taken without a Nicol for the iron spectrum in the blue and violet regions and include most of the 

 lines mentioned by Zeeman (30) as showing a difference in the intensity or in the spacing of the violet and 

 red components. These plates were taken with a field-strength of 19,500 gausses. A set of measure- 

 ments was made for the sharpest triplets occurring in this region to test the question of a difi'erence in 

 the spacing of the violet and red components from the central line. The method was to make settings 

 successively on the violet, central, and red components, and then repeat in the inverse direction, con- 

 tinuing until four sets of readings were obtained from which the mean distance to each side component 

 was computed. The measurements given in Table 6 are the mean of two independent sets taken in this 

 way, which in general agreed closely. Thus each value of AX is the mean of eight determinations of the 

 interval in question. The values of AX are not reduced to the standard field. Differences in favor of the 

 violet interval are -f , those in favor of the red interval . 



Table 6. Spacing of Violet and Red Components of Iron Triplets from the Central Component. 



51 



