320 Dr. C. Davison—British Earthquakes. 
which hades towards the north and which is responsible for the 
stronger earthquakes of the series. : 
Earth-shake at Stanhope (Weardale): December 2, 1909. 
An earth-shake was felt in the mining district of Upper Weardale 
shortly after 1l a.m. So far as can be judged from the small number 
of records, the disturbed area was about 7 miles in diameter and 
about 89 square miles in area. The centre is approximately in 
lat. 54° 45:1’ N., long. 2° 5:0’ W., or 3 miles west of Stanhope. The 
shock consisted of one series of vibrations, of intensity 4, and lasting 
about two seconds. The sound was compared to a heavy train passing, 
the fall of snow from the roof, or the firing of a heavy shot in a quarry. 
At Boltsburn a vibration, accompanied by a heavy rumble, was felt 
in two parts of the mine, and it was at first thought that a heavy fall 
had occurred.!. The small disturbed area, the nature and brevity of 
the shock and sound, and the disturbance in the mine at Boltsburn, 
all point to a superficial slip precipitated by the working in the mines 
as the cause of the earth-shake. 
Spurious Earthquakes. 
Tiverton district: May 25, 1909.—At about 12.55 p.m. shocks 
were felt at several places in East Devon between Honiton and 
Tiverton. Windows rattled violently, and indoors tremors were felt, 
which lasted, with short intermissions, for 15 minutes. At Uffculme 
a peculiar noise, unlike thunder, was heard for 7 minutes. At other 
places the sound was compared to the rumbling of heayy guns. That 
this was the origin of the disturbance is clear from the evident 
transmission of the waves through the air, the long duration of the 
disturbance, the nature of the sound, and from the fact that at the 
time mentioned heavy gun-firimg took place in the Channel off 
Weymouth. Honiton is 35 miles and Tiverton 50 miles west-north- 
west of Weymouth. 
Uyeasound (Shetland Islands): October 9, 1909.—A disturbance, 
supposed to be that of an earthquake, was felt at Uyeasound, in the 
island of Unst, at about 2.10 a.m. The shock, which was of intensity 5, 
consisted of two parts, separated by an interval of 9 seconds. The 
first and stronger part lasted 28 seconds, and the second 12 seconds. 
The accompanying sound resembled the noise of wheelbarrows, 
changing, about the time when the shock was strongest, to that of 
heavy wagons passing. 
So far as I can ascertain, the disturbance was noticed by only a few 
persons. The duration of the double disturbance is of course far too 
great for a British earthquake, but observers of a true earthquake 
occasionally err quite as widely in their estimates. It seems clear, 
however, that a shock so strong as that reported would have been felt 
by many persons over a wide area. It is possible that it was caused 
by thunder, which is said to have been heard the same morning. 
1 IT am indebted to the kindness of my former teacher, Professor G. A. Lebour, 
for the first records of this earth-shake. 
