BETWEEN SUN-SPOT FREQUENCY AND TEREESTEIAL MAGNETISM. 1/1 



spending case at Pawlowsk, a rough measure of the amplitude of the fluctuation 

 throughout a sun-spot period. 



In all the elements included in Table XIV., as we pass from the range of the 

 diurnal inequality to the mean absolute daily range, and thence to the mean monthly 

 range quantities increasingly influenced by magnetic storms we see that whilst 

 a increases, b increases in a greater ratio, so that b/a notably rises. 



The fall of l>/a as we pass from the mean monthly to the annual ranges in D and V 

 may not improbably possess no real significance, but a similar phenomenon, it should 

 lie remembered, presented itself in the corresponding Pawlowsk results in Table VII. 



TABLE XIV. Katharinenburg (Units 1' in D and I, ly in H and V). 



'23. Table XV. shows the excess of observed over calculated values at Katharinen- 

 burg ; it answers to Table VIII. for Pawlowsk. 



The results for the diurnal inequalities in 1), H, and I in Table XV. are similar to 

 the corresponding "all" day results in Table VIII., but on the whole show a slightlv 

 less close agreement between theory and observation. In V, however, the agreement 

 is distinctly better at Katharinenburg than at Pawlowsk. 



In the case of the absolute daily range the agreement between observed and 

 calculated values is particularly good in D, and it is closer in all the elements than at 

 Pawlowsk. This may be ascribed to the fact that magnetic disturbances are larger 

 at Pawlowsk than at Katharinenburg. 



The difference between the observed and calculated values in the monthly range 

 is somewhat large, and there is now clear indication that sun-spot frequency is not 

 by itself a sufficient guide. The observed values in 1893 are conspicuously below, 

 and those in 1892 and 1894 conspicuously above, the calculated. The deficiency in 

 the observed values in 1895 and the excess in 1898 are also marked. Even in the 

 absolute daily range in Table XV. there is a distinct depression in the observed 

 values in 1893 and corresponding enhancement in 1892, though not to the same 

 extent as in the corresponding case at Pawlowsk (see Table VIII.). 



z 2 



