27tf Mr. N. A. Kent on the Zeenian Effect. 



I have investigated are given in Table I. Table II. contains 



in homologous positions the calculated values of -^j as ob- 



X Jo. 



tained from measurements made on my plates together with 

 Reese's and Preston's results. Table III. is obtained from 

 Table II. by making corrections (fully justified *) . Owing 

 to the fact that, to obtain sufficient separation, it was necessary 

 to use a field of over 26,000 c.G.s. units, and that conse- 

 quently, as the " droop " in the H-AX curves before mentioned 

 (see sections 1 and 2) is not the same for all lines, a com- 

 parison of r-zYr is not possible until certain corrections have 

 been made. 



Table III. 



AX 

 X 2 H 



- X 10 5 , corrected values. 



1st Subordinate. 



2nd Subordinate. 







n — 4. 



»="3. 





Kent's results. 



Eeese's. 



Preston's. 



ii — 4 





52 



8-8 



151 



16-9 



150 



120 

 3 



169 

 1 



15-2 



2 



10-7 

 3 



17 

 1 



14-8 



2 



11-1 

 3 



4-8 

 1 



8-4 

 2 



14-9 



3 



Set 1 



2 



3 



1 



2 



Table III. shows :— 



AX . 



1st. That Preston's law, ^fj is a constant for homologous 



lines — established by him for the homologous lines of zinc, 

 cadmium, and magnesium given by n = 3 in the second sub- 

 ordinate series — appears to hold for the homologous lines in 

 mercury and cadmium. 



2nd. That, within the limits of accuracy of measurement 



AX ? 



r-^rris the same for homologous lines given by n — ^ in both 



the subordinate series for zinc, cadmium, mercury, mag- 

 nesium, and calcium. This assumes that the lines not 



* The necessary corrections were determined by quite a complete study 

 of the " droop " of homologous lines. 



