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far west as Barrahead, though how much farther it was propagated 
into the Atlantic it is impossible to say. 
4. That the range of the earthquake or distance to which the 
wave was propagated was greater over the sea than over the land. 
5. That the earthquake was not a simultaneous shake over the 
disturbed area, but was produced by a wave propagated from a 
centre. 
6. That the undulation seems to have been chiefly of an “ up and 
down ” character like a wave of the sea, and that, calculating the 
breadth from the mean velocity of transit, and the minimum 
duration of the shock, it appears to have been fully 1100 feet 
in breadth. 
7. That the observations warrant the assumption that a spot near 
Phladda lighthouse was the source, and calculating the velocities of 
transit with a point 13 miles S.S.W. of Phladda as a centre, the 
wave travelled with a greater velocity over the sea-basin than over 
the land, probably due to the fact that over the sea there was a 
thinner and lighter crust to throw into vibration, the average velocity 
on sea journeys being 6*74 geographical miles per minute, and the 
average velocity on land journeys 4 # 65 miles per minute, the mean 
of the whole being about 5 J miles per minute. 
8. That the source of the earthquake lay at or near the great 
fracture, which runs in a south-westerly direction from Inverness, 
and that the shock was probably due to a rupture of the crust of 
the earth at this very distinct line of fracture. 
9. That all the observers who heard noises agree in stating that 
it was a “ rumbling ” sound. 
10. That of the fourteen observers within a radius of 38 miles 
from the source, who felt the shock, thirteen of them mention 
having heard the rumbling sound, and none of the other observers in 
Scotland mention noise as an accompaniment of the earthquake, 
and hence that the noise was confined chiefly, if not entirely, to 
places situated near the source. 
11. That the stations where the noise was heard were for the 
most part situated on hard dense rocks with little or no soil near 
them. 
12. That the average duration of the disturbance was 4*4 seconds, 
for observers within the sound area. 
