166 A. ÏANAKADATE. 



The depths of the inuige as determined by the points of 

 intersections of those lines whh the vertical through the epicenter 

 are 



I. II. III. IV. V. Mean. 



940 1030 1090 1040 950 1010 kilum. - 



and the distances f* of these points from the respective points 

 taken in the data are 



I. TI. III. IV. V. 



,o = 24;J0 2240 2070 1800 1.370 kiluiu. 



From those values and zenith distances we get by (3) the values 



image 



2 fl OZ' 2 //' dlV 



of the strength of the image 



m = 



1 4- 3 cos 2c Oz 3 sin 2c dz 



I. II. III. IV. 



= -2.92 -1.42 -1.10 - .94 



The values of m increase regularly Avith the values of y. This 

 might Ije either due to systematic errors in the empirical formuhe 

 for isomagnetics, or else to the state of distribution of magnetism 

 being widely spread over the region under consideration. 



Taking the first supposition, Ave may adopt the mean value 

 of lib as the approximate strength of the image, which give the 

 disturbance of the vertical held at the epicenter. 



_ 1.41 X 10"' , ^^, ^, . , ^, 



(i0107>ri0'"=~-^^^ ^'^'^' ^^"^^'^• 



Fig. 13 gives the residual intensities of the vertical and 

 horizontal components of the terrestrial magnetic field after deduct- 

 ing those due to the mean magnetization, or what corresponds to 



