132 F. OMORi : 



oscillatioijs is naturally the same always in both horizontal 

 coin})onents. 



14. 1 will next notice three more instances ot" storms of 

 pulsatory oscillations. 



Pulsatory oscillations on the 21st and 22nd May, 1898 ; EW 

 component. The range of motion of one of the greatest movements 

 was 0.16 mm. and its period 5.6 seconds. The motion was not 

 uniform but presented, as is usually the case, alternations of 

 maxima and minima, whose average interval was about 1 

 minute. The average period of the larger oscillations was 5.5 

 seconds, while that of the smaller in the same epoch was 5.2 

 seconds, the general average period being 5.4 seconds. 



Pulsatory oscillations on the ôth and 6th June, 1898; EW 

 component. The maximum range of motion was 0.15 mm. 

 The average j>eriod of the larger oscillations was 5.7 seconds, 

 while that of the smaller was 5.2 seconds, tlie general average 

 period being 5.4 seconds. 



Pulsatory oscillations on the 14th and 15th November, 

 1898. The average period of vibration was 4.5 seconds, the 

 maximum range of motion being about 0.07 mm. in each hori- 

 zontal component. The diagram of the NS component is given 

 in fig. 11. 



15. The pulsatory oscillations, as to whose reality there 

 can be no doubt, have also been observed by myself with a 

 Paschwitz Horizontal Pendulum newly constructed by Messrs A. 

 Repsold and Sons for the Imperial Earthquake Investigation 

 Committee. Fig. 13 (PI. VI) exhibits a typical specimen of such 

 movements obtained on the 10th April, 1898, in the Univer- 

 sity grounds ( Hongo, Tokyo), the rate of motion of the 

 photographic paper being 30 cm. per hour, and the proper 



