6i C. Davison — British Earthquakes. 



These observations are not sufficiently numerous to enable isoseismal 

 lines to be drawn with any accuracy. But it is evident that the 

 isoseismal of intensity V. could not be very distant from the boundary 

 of the disturbed area, as drawn upon the map. We may therefore 

 conclude that this boundary' corresponds to an isoseismal of intensity 

 between IV. and V., and probably nearer V. than IV. 



Sound-phenomena. — All the places w^hei'e the characteristic earth- 

 quake-sounds are known to have been heard are marked on the map 

 with a'small cross {-\-) through the spot indicating the position of 

 the place. They are unfortunately very few in number, only 19 out 

 of the 53 places from w^hich I'ecords have been received. But, on 

 the other hand, there are several places where the shock was felt, 

 and where it is expressly stated that no sound was heard. These 

 are Leith, Trinity, Burntisland, and Polmont, and they are indicated 

 on the map by a stroke ( — ) drawn through the spot representing 

 the place. It is also important to note that, whilst records from 

 Edinburgh (where the intensity was V.) are numerous, 28 in number, 

 in only two cases is there any mention made of earthquake-sounds. 

 Again, at Peebles (where the intensit}'^ was IV.) out of four separate 

 accounts which Dr. Gunn sent me, two are records of the sound- 

 phenomena only, the shock being apparently not felt in these cases. 

 From these facts, two conclusions may be drawn : 



(1.) The area throughout which the sounds were heard was not 

 coextensive with the disturbed area; a fact previously noticed in the 

 case of other earthquakes. 



(2.) The centre of the sound-area was not coincident with that of 

 the disturbed area, but lay probably about 2^ miles to the south or 

 south-east of the latter. It will be seen that a similar inference 

 may be made in the case of the Lancashire earthquake of Feb. 10. 

 I believe that this conclusion is new, and will be found to throw 

 light on the origin of earthquake-sounds. 



In their character the sounds accompanying the Edinburgh 

 earthquake do not seem to have been in any way unusual. The 

 following are the only detailed descriptions I possess : 



Balerno : like the falling of a heavy mattrass. 



Bathgate : as if a heavy waggon had passed along the street. 



Cockburn : as though a large tree had fallen near the house. 



Edinburgh: (1) like the rumbling of a passing coach; (2) a 

 loud sharp crash, as if the door had been slammed in an extraordinary 

 manner. 



Harperrigg : like the firing of a time-gun twice, accompanied, 

 with an oscillation. 



Kirknewton : a loud clanking noise. 



Linlithgow : a suppressed rumbling sound. 



Peebles : like the passing of a heavy cart. 



Eatho : like the passing of a heavy traction-engine. 



In every place the duration of the sound seems to have been very 

 short. This is evident from some of the above accounts, and 

 probably, as before remarked, the duration of the sound is included 

 in the estimates of the duration of the shock given above. The 



