1897.] on Becent Advances in Seismology. 329 



unknown and not required in countries free from earthquakes. That 

 these rules, which take into consideration that structures have to 

 withstand stresses due to more or less horizontal displacements at 

 their foundations, have been followed, is in itself a testimony that 

 engineers regard them as being worthy of consideration, and we now 

 feel assured that when an earthquake like that of 1891, which cost 

 Japan 10,000 lives and an expenditure on repairs of at least 

 30,000,000 dollars, is repeated, the losses will be comparatively 

 trifling. That the new departures in engineering and building 

 practice have proved beneficial has been repeatedly demonstrated. 

 Because experiments showed that earthquake motion at a compara- 

 tively shallow depth was somewhat less than what it was upon the 

 surface, a number of modern and important buildings in Tokio have 

 had given to them deep foundations and are surrounded by open areas. 

 On several occasions these buildings have stood unimpaired whilst 

 neighbouring structures have been badly shattered. 



The tall chimneys of factories, as well as those of ordinary 

 dwellings, have been so far modified that the new forms stand whilst 

 the old forms fall. The greatest material benefits which seismology 

 has conferred upon Jaj^an will, however, probably be found in the 

 radical changes which are taking place in the construction of ordinary 

 dwellings. 



One application of seismometry to the working of railways in 

 Japan has resulted in a saving of fuel of from 1 lb. to 5 lbs. of coal 

 per mile per locomotive. In these and other ways, by following up 

 initiatives created during the last twenty years, Japan has reached 

 a high position, if not foremost, amongst nations who have given 

 attention to seismology. The Government of that empire, recog- 

 nising the value of what has been already accomplished, and that 

 much more is yet oj^en to investigation, have at their university 

 established a Chair of Seismology, a committee which is liberally 

 supported, to make investigations relating to earthquakes an,d their 

 effects, and a seismic survey of their empire. 



When we remember that a single earthquake has often cost Japan 

 a far greater loss of life and an expenditure of jDublic funds at least 

 comparable with that accompanying her recent war, it is not remark- 

 able that her chief interest in earthquakes has been directed towards 

 means to mitigate their effects; by doing which, whilst conferring 

 benefit on herself, she has also conferred benefits upon the earthquake- 

 shaken countries of the world. Notwithstanding this, questions of 

 interest to science have not been overlooked. The object of one series 

 of experiments, which were carried out at intervals extending over 

 several years, was to measure the velocity with which disturbances pro- 

 duced by explosions of dynamite and other substances were propagated, 

 and to study the character of the vibrations as they radiated from 

 their source. Near to an origin a clear separation between normal and 

 transverse movements was observable, which at distances exceeding 

 50 or 100 feet was lost. Single waves as they spread outwards wero 



