144 A.. Imamuea 



were wrecked, and oid}^ one coii)])onent of a seismograph witli the 

 index magnification of two times kept going throughout. The in- 

 struments, however, w^re soon adjusted or repaired, and 6 minutes 

 after the beginning of the quake the following seismographs were 

 running : — 



1. A complete set of seismographs with the index magnification 



of two times. 



2. A complete set of seismographs registering the earth move- 



ments in actual size. 



3. E. W. component seismograph with the magnification index 



of 1.5 times. 



4. N. S. component seismograph similar to No. 3. 



Besides these, two more instruments each with an automatically start- 

 ing record-receiver were available. A few instrument with higher 

 magnification index were running after a day or two. 



4. Actual feeling at Hongo. I was sitting in the Seismological 

 Institute. At first, the movement was rather slow and feeble, so that 

 I did not take it to be the forerunner of so big a shock. As usual, 

 I began to estimate the duration of the preliminary tremors, and 

 determined, if possible, to ascertain the direction of the ymncipal 

 movements. Soon the vibration became large, and after three or four 

 seconds from the commencement, I felt the shock to be very strong 

 indeed. Seven or eight seconds passed and the building was shaking 

 to an extraordinary extent, but I considered these movements not yet 

 to be the principal portion. At the 12th second from the start, acc(^rd- 

 ing to my calculation, came a very big vibration which I took at 

 once to be the begivming of the principal portion. Now the motion, 

 instead of becoming less and less as usual, went on increasing in 

 intensity very quickly and after 4 or 5 seconds I felt it to have reached 

 its strongest. During this ei»och the tiles were showering down from 

 the roof making a loud noise and I w^ondered whether the building 

 could stand or not. I was able accurately to ascertain the directions 

 of the principal movements and found them to have been about N. W. 

 or S. E. During the follow^ing 10 seconds the motion, though still 

 violent, became somewhat less severe, and its character gradually 

 changed, the vibrations becoming slower but bigger. For the next 

 few minutes we felt an undulatory movement like that which we 

 experience on a boat in windy weather, and we were now and then 



