TIME OF EARTHQUAKE, RATE OF PROPAGATION. 
43 
enclose a tahuhited list of times and deductions for the stations in Great Britain 
I have used Zocppritz tables and a 14-inch globe for measurements ; — 
Time of orrunenre of the Srimangal Earthquake deduced from ohservatiotifi in Great 
Britain, G.M.T. Use made of Zoepprilz Tables. Also 14" globe for measure- 
ment. 
A 
as mea- 
sured 
on 
globe. 
A 
calcu- 
lated 
from 
S— P. 
Arrival 
of P. 
Arrival 
of S. 
Time at origin 
deduced from A 
measured on globe. 
Time at 
origin 
deduced 
from 
S— P A. 
Aberdcon 
T2°-3 
70°-5 
10 33 36 
10 42 48 
10 22 4 
10 21 54 
10 22 16 
West Bromw icli 
73°-3 
70°-8 
10 33 37 
10 42 51 
10 21 59 
10 21 45 
10 22 15 
Kskdaloniiiir . 
74*0 
iro 
10 33 40 
10 43 0 
10 21 58 
10 21 46 
10 22 10 
Bidstou 
74'-0 
72°-6 
10 33 38 
10 43 2 
10 21 56 
10 21 48 
10 22 4 
G.M.T. 
I.S.T 
Average by A mcasiirod on globe 
10 21 
54 
15 51 
54 
Average by A calculated froiu S — P 
10 22 
11 
15 52 
11 
From the average of three methods you will see we obtain the figure 10 hours 
22 minutes 2 seconds (or 15 hours 52 minutes 2 seconds I.S.T.)." 
" Riverview, Sydney, lies 80° 1' on the directly opposite side of your epicentre 
from here. Their times are : — - 
P . . . 10 34 24 S . . . 10 44 33 
by the re.spective methods used on the above list the time at epicentre, works 
out : — 
(1) From arrival of P 10 22 4 
(2) „ „ S 10 22 8 
(3) By measured on globe 10 22 0 
Average . . 10 22 4 
only two seconds different from the average of the Bi-itish Stations. 
Professor H. H. Turner's hypothesis (1918). — Professor Turner, F.R.S., in the 
1918 Annual Report of the Seismological Committee of the British Association, 
pointed out that when a pair of .stations are on directly opposite sides of an epi- 
centre — and preferably distant towards 90° — the conditions provide an oppor- 
tunity for checking the values of SP in the tables. 
In this instance we have two stations, Riverview and West Bromwich, distant 
from the epicentre 80° 1' and 73° 3' respectively, and where the great circle, 
joining the two passes within 270 miles of the origin, 
p2 
