s. NakaiTiura and K. Honda : 



Introduction. 



The observation of seiches, or the oscillatory movements of 

 the entire body of water of a lake, was begun in Japan in 1901 

 by the Earthquake Investigation Committee at the suggestion of 

 Professor Nagaoka. The present paper gives a summary of the 

 results obtained from these observations. Up to 1901 no one had 

 taken the trouble to make such observations except Burton.* 

 He, in 1891, had noticed that the pebbles on the shore of Hakone 

 lake were regularly covered and uncovered by the water, the 

 length of the period being 55 seconds. This however, as we shall 

 see later on, is by no means one of the principal oscillations in 

 that lake. It must rather have been a secondary undulation 

 peculiar to the particular point of observation. The names of the 

 lakes, where observations have been made, together with the 

 dates and the names of the observers, are given in the following 

 table. 



TABLE 1. 



Lake. 



Date. 



Observer. 



Biwa 



July 29— Aug. 23, 1901. 



Nagaoka, Nakamura, YosMda. 



Hakoné 



Aug. 28— Sept. 1, 1901. 



Nagaoka, Honda, Kuwaki,. Yoshida. 



Biwa 



Sept. 6—30, 1901. 



Honda, Kuwaki, Yoshida. 



Hamana 



Aug. 20—26, 1902. 



Nakamura, Honda, Yoshida, Iwamoto, Inouye. 



Kawaguchi 



Aug. 29- Sept. 1, 1902. 



1. „ .. » 1. 



Yamanaka 



Sept. 1—4, 1902. 



M I) » i> )i 



Töya 



Aug. 18-19, 1905. 



Honda. 



Cliüzonji 



Aug. 27—23, 1905. 

 July 6-8, 1906. 



,. 



As we shall see presently, in some of the lakes like Hakoné 

 and Biwa, the i)henomena was very prominent, while in others 



* Trans, of theSeismological Society of Japan, Vol. XVI, 1891. 



