SEISIMOMETEY. 15 



of which holds a ball in its mouth. Underneath these 

 heads there are eight frogs so placed that they appear to 

 watch the dragon's face, so that they are ready to receive 

 the ball if it should be dropped. All the arrangements 

 which cause the pillar to knock the ball out of the dragon's 

 mouth are well hidden in the bottle.' 



' When an earthquake occurs, and the bottle is shaken, 

 the dragon instantly drops the ball, and the ftog which 

 receives it vibrates vigorously ; any one watching this in- 

 strument can easily observe earthquakes.' 



With this arrangement, although one dragon may 

 drop a ball, it is not necessary for the other seven dragons 

 to drop their balls unless the movement has been in all 

 directions ; thus we can easily tell the direction of an 

 earthquake. 



* Once upon a time a dragon dropped its ball without 

 any earthquake being observed, and the people there- 

 fore thought the instrument of no use, but after two 

 or three days a notice came saying that an earthquake 

 had taken place at Eosei. Hearing of this, those who 

 doubted the use of this instrument began to believe 

 in it again. After this ingenious instrument had been 

 invented by Choko, the Chinese Grovernment wisely 

 appointed a secretary to make observations on earth- 

 quakes.' 



Not only is this instrument of interest on account of 

 its antiquity, but it is also of interest on account of the 

 close resemblance it bears to many of the instruments of 

 modern times. 



Another earthquake instrument also of Eastern origin 

 is the magnetic seismoscope of Japan. 



On the night of the destructive earthquake of 1855, 

 which devastated a great portion of Tokio, the owner of a 

 spectacle shop in Asakusa observed that a magnet dropped 



