Seismological Investigations. 99 



organization and active operations of the Seismological Society 

 of Japan. Earthquakes are there so frequent that a rare oppor- 

 tunity for their study is offered. A few foreigners temporarily 

 residing in the country, together with a number of native 

 scholars, joined in the prosecution of seismic investigations and 

 in the establishment of the Society. Its published transactions, 

 already filling ten volumes, contain nearly all of seismology that 

 is in advance of the old methods. Progress has been made 

 mostly in the direction of improvement in seismographs, and is, 

 in a great degree, due to better methods for securing the very 

 desirable " steady point " and to a recognition of correct dynam- 

 ical principles in the construction of the instruments. 



The well known horizontal pendulum or "bracket" seis- 

 mographs of Ewing,* Gray,f Milne and others, have greatly 

 increased our facilities for research and, in fact, have afforded 

 about the only fairly reliable information concerning the real 

 movement of the earth-particle. 



Notwithstanding the comparative infrequency of earthquakes 

 in the United States, many advantages for their study are offered 

 here. Among others may be mentioned the following : the 

 great extent of country which could be brought under one sys- 

 tem of observations ; — a generally intelligent population, fur- 

 nishing a corps of willing and reliable observers ; — the extensive 

 system of telegraph lines ; and, perhaps superior to every other, 

 the wide distribution and almost universal use of " standard 

 time " throughout the country. In consideration of these ad- 

 vantages and of the fact that certain portions of the country 

 appear to be subject to occasional seismic disturbances, it has 

 seemed desirable that an extended and well planned series of 

 observations should be undertaken, and that seismology should 

 not be in the future, as it has been in the past, a somewhat 

 neglected science. 



Among American geologists especially, there has always been 

 great interest in the subject, and a good deal has been written 

 concerning geological theories of earthquakes. Rockwood;}: has 

 done excellent service in his publication of frequent catalogues 

 of earthquakes in America, together with such information re- 

 garding them as could be incidentally gathered. But the first 

 important step towards an elaborate and systematic study of 

 earthquakes was taken a few years ago by the Director of the 

 IT. S. Geological Survey in establishing what has been known 

 as the "Earthquake Commission." The work of this body, 

 during its existence, consisted mainly in the discussion of 

 methods of observation, together with the preliminary arrange - 



* Trans. Seis. Society of Japan, vol. ii. 

 f Trans. Seis. Society of Japan, vol. iii. 

 X This Journal, from 1872 to the present time. 



