380 . DR. CHARLES DAVISON ON THE [ Aug. 1902, 
At Dochgarroch, and other places within the epicentral district, 
walls were cracked, chimneys thrown down, and lintels loosened. 
But, for this country, the most remarkable effect of the earth- 
quake was a long crack in the northern bank of the Caledonian Canal, 
near Dochgarroch Locks. It was formed in the middle of the 
towing-path, and could be traced at intervals for a distance of 
200 yards to the east of the Locks and 400 yards to the west, being 
often a mere thread, and in no place more than half an inch wide. 
Shortly after the earthquake, heavy showers of rain obliterated 
the fissure; but Col. Mackinnon informs me, on the authority of 
the engineer in charge of the canal, that there can be no doubt 
whatever that the crack was caused by the earthquake. 
Epicentral area.—tThe district within which slight damage to 
buildings occurred is bounded by the isoseismal 8, the innermost 
line in Pl. XI (shown on a larger scale by the dotted line in Pl. XII). 
The curve is 12 miles long, 7 miles wide, and contains 67 square 
miles: its longer axis running N. 33° E., and 8. 33° W. The 
centre of the curve is about 14 miles east-north-east of Dochgarroch, 
and three-quarters of a mile on the south-east side of the fault-line. 
Isoseismal lines and disturbed area.—The isoseismal 8 
is probably the only curve of the series that is accurately drawn 
throughout. In every other case, owing to the scarcity of observa- 
tions in the West of Scotland, there are portions which must be 
regarded as doubtful. 
Except towards the west, there are sufficient points to determine 
the course of the isoseismal 7. Its length is 53) miles, width 
35 miles, and area 1500 square miles; the longer axis is directed 
N. 32° E., and 8. 32° W., and is therefore nearly parallel to that 
of the isoseismal 8. The distance between the isoseismals is 9 
miles on the north-west side, and 14 miles on the south-east side. 
Records of intensity 6 were difficult to obtain, as most observers 
slept in darkened rooms, As drawn on the map in the position 
which appears to me most probable (Pl. XI), it includes a district 
105 miles long, 87 miles wide, and containing 7300 square miles. 
The distance between the isoseismals 7 and 6 is 214 miles on the 
north-west, and 31 miles on the south-east side. 
The path traced out for the isoseismal 5 is entitled to a greater 
degree of confidence. Its length is 157 miles, width 143 miles, 
and area about i7,000 square miles. The distance between the 
isoseismals 6 and 5 is 211 miles on the north-west, and 34} miles 
on the south-east side. 
For the isoseismal 4, there are again but few determining points, 
and the curve could not have been drawn in the doubtful parts 
without reference to the preceding isoseismal. In the extreme 
North of Scotland, records come from Wick, Castletown, and other 
intermediate places. From the North-west of Sutherland and from 
Skye, observations are entirely wanting. The intensity was, how- 
ever, equal to 4 at Tobermory, in the island of Mull. Towards the 
south, there are good accounts from Skelmorlie (in Ayrshire), Paisley, 
