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SEISMOLOGICAL INVESTIGATIONS. 213 
therefore made of M. Lecointe, of Brussels (who was deputed by the Inter- 
national Astronomical Union to deal with astronomical telegrams), whether 
a supplementary seismological service could be arranged. [It may be 
remarked that, although an International Geophysical Union was con- 
stituted at Brussels in 1919, at the same time as the Astronomical Union, 
it was not found possible to initiate the seismological branch of it until the 
formal dissolution of the former International Seismological Association had 
been completed. Hence the astronomical body was approached as the best 
available means under the circumstances.] M. Lecointe replied that a tele- 
graphic code had already been arranged at Strasbourg, which Professor Rothé 
kindly communicated to me. Since then we have exchanged various telegrams 
in this code, with advantage, at a Aha to us. 'For instance, the news from 
America about the quake of 1921, February 4, was again misleading, but the 
wire from Strasbourg prevented our being perturbed by it. Inquiry has been 
made whether exchanges cannot be arranged across the Atlantic in this code, 
and negotiations are still proceeding in the matter. Meanwhile a further step 
has been taken in the dissemination of Strasbourg intelligence from the Eiffel 
Tower. Of this we have not as yet been able to take advantage, partly because 
of the absence through illness of Miss Bellamy, and partly because there have 
been few large earthquakes recently. 
The following are the particulars of the code :— 
Telegraphic Code for Earthquakes. 
dd/aa/p p/bh/mm ss /ttt D,D,DDD. 
dd=date. 
aa=azimuth of epicentre from 10° to 10°, counting from N. through E. (01-36) 
based on any c/ear indications of the trace. The addition of 50 (51-86) 
indicates that the azimuth is uncertain by | 180°. The figures 91-98 
indicate that the direction is vague and estimated only to nearest 45° ; 
99 indicates that no azimuth determination has yet been made; 00 that it 
seems impossible. 
pp refer to phases P and §; the first (1-4) concerns P, and second (5-8) 5, 
according to the table below. ‘The figure 9 for either P or S indicates 
that the minute signal interferes with beginning. 
hh mm ss are hours minutes and seconds of P. 
ttt is difference S—P in seconds. 
D,D, gives difference P—P in seconds for close earthquakes; if this difference 
is not clear, D,D, is replaced by 99. 
DDD is distance in kilometres for close quakes. 
D,D,DDD is distance in kilometres for distant quakes. 
1 2 see: Sarena ern 
Phase * ae ! 
P iP P&P hae: 
clear 
5 6 vy | 8 
Phase A sii eotorer distives 
S is 8 es | Uncertain 
Azimuth of Epicentre from two adjacent Stations. 
In the course of trying to identify the epicentre of the great earthquake of 
1920, December 16, a small point of procedure suggested itself which it may be 
useful to note. 
Suppose we have two stations, say O(xford) and D(yce), whose distances 
EO and ED from the epicentre E are known, We can describe circles on the 
