44 REPORT— 1904. 
numbers on the map indicate that such determinations are accompanied 
by uncertainty. 
Speaking generally, it may be inferred that about 50 per cent. of the 
Fies. 1 AND 2. Milne’s Horizontal Pendulum (seismograph) with new 
L sray 
recording arrangement, 
BRASS RAILS 
| 
6 FEET 
3 SCALE ‘ 
; 2 2 METRES. 2 
large earthquakes have disturbed the world’s surface as a whole, whilst the 
remainder have only affected areas equal to those of single continents. 
The greatest activity is again along the Libbey Circle (radius 70° and 
centre 180° E. or W. long., and 60° N. lat.). Marked activity has 
taken place at the junction of regions E. and F., and in the eastern por- 
