ON THE VOLCANIC PHENOMENA OF JAPAN. 225 



3. With wind and no tremors 60 cases : — 



(a) Cases where tremors ought to have occurred . 9 cases. 

 (h) Cases where it is doubtful whether tremors ought 



to have been observed . . . . . 51 ,, 



4. With wind and tremors . . . . . . 65 ,, 



6. With local wind and no tremors ..... 101 ,, 



6. With local wind and tremors . . . . . 17 ,, 



Total 945 „ 



In 1885 tremors were therefore recorded 133 times. The obvious ex- 

 planation for 65 cases (50 per cent.) when tremors were very marked is 

 that they were produced by stormy winds which were then blowing. In 

 34 cases (25 per cent.) the ti'emors inay have been produced by stormy 

 winds which had been blowing a few hours previously or by strong local 

 winds. The remaining 34 cases (25 per cent.) may have been of subter- 

 ranean origin. In these latter cases, however, the tremors are feeble and 

 of short duration, ivhile ivhen the tremors have accompanied luind they have 

 been of considerable amjdittide and of long duration. That tremors are in 

 great measure due to wind receives support from the fact that when it 

 has been calm in Central Japan tremors which have always been very 

 slight have only been observed in less than 5 per cent, of the times of 

 observation. 



Summary. 



The preceding epitomised analyses apparently point to the following 

 results : — 



1. Earth- tremors are more frequent when the barometer is low than 

 when it is high, but even with a low barometer tremors are not always 

 observed. 



2. With a steep barometric gradient tremors are almost always ob- 

 served, but with a small gradient it is seldom that they are recorded. 



3. The stronger the wind the more likely it is that tremors should be 

 noted. 



4. When there is a high wind in Tokio and no tremors such wind has 

 almost invariably been local, or of short duration, or blowing in from the 

 Pacific Ocean. Such winds are rarely accompanied by tremoi'S. 



5. When there has been no wind in Tokio, and tremors have been 

 observed, in most instances there has been a strong wind in other parts 

 of Central Japan. In the case of winds working up Japan from the 

 S.W. the tremors in Tokio have been very marked, these being recorded 

 in Tokio several hours before the arrival of the wind. Sometimes 

 tremors appear to be due to a wind which had been blowing a few hours 

 previously. 



6. With a general calm in Central Japan it is extremely rare to 

 observe tremors, and even if they are observed they are extremely slight. 



7. Earthquakes and earth-tremors do not appear to be connected with 

 each other. 



Although the above conclusions are founded upon a fairly long series 

 of observations and their importance is great, especially to all who are 

 engaged in meteorological investigations, it is hardly yet justifiable to 

 put them forward as established laws until the observations have been 

 repeated. So far as my investigations have gone, it certainly appears 



1887. Q 



