i03 



Hg 5461, tlie most intense mercury line. 



Cd 5086, intense cadmium line. 



ZnCd 4805, a l»lue zine and a cadmium line, almost coinciding. 



Zn 4722, blue zine line. 



Hg 4358, ,, mercury line. 



For every slit image there have been made four readings, two 

 for every direction of current, the strength of the current having 

 been read every time. Then the angle between the two positions 

 of the analyzers has been derived from the means of the corre- 

 sponding readings, and the angle of rotation for 1 ampère found 

 through division by the sum of tiie two strengths of current that 

 differ iuit little. 



The results of some six series of oltservations are recorded in 

 the subjoined table. • 



Magnetic rotation in minutes, for 1 amp. 



6 Mean 



/gauss. cm. 



0.5780 

 0.5461 

 0.5086 

 0.4805 

 0.4722 



59.8 I 60.1 



74.9 75.2 

 101.6 101.0 

 128.1 128.4 

 140.5 139.6 



0.4358 208.7 209.6 



I i 



60.1 j 60.2 1 60.0 



75.3 74.9 75.1 



100.1 ] 100.4 98.9 



! 



129.4 1 129.3 j 129.2 



140.1 I 141.9 , 138.8 



208.8 , 209.5 209.2 



60.0 

 75.0 

 100.2 

 127.8 

 141.1 

 208.3 



60.0 

 75.1 

 100.4 

 128.7 

 140.3 

 209.0 



0.01618 

 0.02023 

 0.02705 

 Ü. 03468 

 0.03782 

 0.05633 



Then observations have been made with arc light for a number 

 of different wavelengths. The wavelength was found by illuminating 

 the collimator slit by means of a mirror with a quartz amalgam 

 lamp, and adjustment to the slit images lying nearest to the place 

 in the spectrum where observations were to be'madc. From this 

 the wavelength at the place of observation was derived by means 

 of a dispersion curve of the prism. These adjustments always took 

 place immediately before or after those of the position of the 

 analyzer. 



To be able to calculate the rotation constant q per gauss cm., 

 the test tube is then tilled with distilled water, and tiie magnetic 

 rotation is measured for two diflerent wavelengths. By the aid of 

 the constant of rotation for water and the magnetic rotation dispersion 



