EFFECTS PEODUCED UPON BUILDINGS. 99 



felt throughout Tokio, the strength of which, as judged 

 by our feelings, was above that of an average shock. As 

 registered by one of Palmieri's instruments, it had a 

 direction S.S.W. to N.N.E. and an intensity of 11°. On 

 the same day there were several smaller shocks having 

 the same direction, and these were succeeded by others 

 on the 9th of the month. 



Immediately after these shakings it was discovered 

 that almost every arch in the internal walls of the build- 

 ing here referred to had been cracked across the crown 

 in a direction about N. 40° W. All the other arches of 

 the building, of which there were a great number in walls 

 at right angles to the direction of the shock, were found 

 not to have sustained any injury. To this statement, 

 however, there was one exception, which was subsequently 

 proved to have been due to a settlement taking place. 



After examining these cracks the only cause to which 

 they could be attributed was the series of shakings which 

 they had just experienced. It seemed as if the heavy 

 walls right and left of the arches had been in vibration 

 without synchronism in their periods, and as a conse- 

 quence the arches which connected them had been torn 

 asunder. 



Although the time at which the cracks were formed 

 and the peculiar positions in which they were only to be 

 found pointed distinctly to their origin, to be certain that 

 they were not due to settlement of the foundations, hori- 

 zontal lines were ruled upon the brickwork and from time 

 to time subsequently observed. 



The points to which the various cracks extended were 

 also marked and observed. Beneath the walls as founda- 

 tions there were beds of concrete about three feet thick 

 and ahout ten feet in width. These had been under the 

 pressure of the partially built walls for two years before 



