XC PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 896,. 



20 years at the Imperial College of Engineering, Tokio, Japan, and 

 devoting his time and income to the investigation of earthquake- 

 phenomena in that centre of remarkable disturbance, has now 

 returned home from Japan and has established a station for seis- 

 mological observations in the Isle of Wight. 



Some of his latest researches on the propagation of earthquakes 

 to great distances have led him to most interesting conclusions. 



In the case of the Argentine earthquake of 1894 Milne was 

 successful in showing that a large disturbance might be recorded 

 at the antipodes of its origin. The pronounced movements of an 

 earthquake travel over paths around an epicentre at a rate of 

 2 or 3 kilometres per second, and they are transmitted, at the 

 same rate, to places distant more than a quarter of the earth's 

 circumference. Preceding these pronounced movements which 

 apparently radiate as quasi-elastic gravitational waves, minute 

 tremors are observable, which, in travelling from Japan to Europe, 

 apparently outrun the main disturbance by half-an-hour. The 

 velocities at which these are propagated have been estimated as 

 varying between 8 and 20 kilometres per second. 



Assuming these determinations to be approximately correct, it 

 is difficult to escape the conclusion that the motion, instead of 

 having been transmitted through the crust of the earth, has been 

 transmitted through its interior. Prof. Milne writes : — ' "When a 

 number of properly-equipped observing- stations have been esta- 

 blished around our globe, it seems likely that we shall be in a 

 position to state definitely the velocity with which motion travels 

 along paths at varying depths in the earth's interior. From the 

 little already accomplished, it appears that, if our globe is capable 

 of transmitting motion two or three times more quickly than steel, 

 it has an effective rigidity very much higher than has hitherto been 

 supposed.' ■ 



Thanks to these researches and experiments, carried out in 

 cooperation with the late E. von Rebeur-Paschwitz and other 

 observers in Europe, we may hope, possibly within a few years, to 

 have a definite solution of what has heretofore been to geologists 

 truly a terra incognita — the nature of the structure of the interior 

 of the earth. 



On his retirement in 1895, Prof. Milne received from the Emperor 

 the well-merited decoration of the Rising Sun, in recognition of the 

 valuable scientific work performed by him during his long residence 

 in Japan. 



