254 REPORTS ON THE STATE OF SCIENCE, ETC. 
The machine at Edinburgh was placed originally at Eskdalemuir in 1915 for com- 
parison with the Galitzin seismographs and removed to Edinburgh in 1919. No. 1 
was supplied to Mr. W. E. Plummer at Bidston in 1914. It was transferred to Oxford 
in exchange for No. 32 (see report, 1927). 
The four additional seismographs for use in India by Dr. Banerji for further 
research on microseisms have been constructed at West Bromwich and delivered, as 
have also the two for the Jammu and Kashmir Government. India is now well 
equipped with Milne-Shaw seismographs, from Kashmir in the north to Ceylon in 
the south. The locations are Srinagar, Agra, Bombay, Alipore, Hyderabad, Colombo 
and Madras. At the last-named station the seismograph is awaiting erection. This 
will form a valuable distribution of stations for recording the shocks in the Far East. 
BULLETINS AND TABLES. 
Mr. Bellamy, who has been in charge of the University Observatory during the 
year, reports that the International Seismological Summary has been issued to the 
end of September 1927. The first, second and third quarters were posted to 298, 307 
and 317 stations respectively. The quarter October-December is in the hands of 
the printers, and the proofs have been read. The manuscript for January-March 
1928 is also ready. Seismological bulletins have been received from fifteen additional 
stations during the year, and eleven new applicants for the Summary have been 
added to the list. There is also a steady demand from publishing firms for the 
publications. The copies thus sold are in addition to the foregoing. It will be seen 
that the progress of the work is being maintained, notwithstanding that the valuable 
help of Prof. Turner has been lost, and that the work becomes greater as new stations 
are added to the list. Itis a source of relief that Miss E. F. Bellamy and Mr. J. Hughes 
have been able to perform the extra work entailed. On fourteen occasions films or 
copies have been sent to other observatories for the purpose of special research. The 
discussion of the revision of seismological tables by Dr. Jeffreys in vol. ii., No. 7, of 
the Monthly Notices of the R.A.S. has been reprinted and issued by the Committee. 
Copies of a Catalogue of Earthquakes in Persia compiled by Sir Arnold T. Wilson 
were also distributed by the Committee. A number of university students have made 
use of the Milne Library during the year. ry 
REVISED SEISMOLOGICAL TABLES. 
By Haroup JEFFREYS. 
During the past year a revision of the Zéppritz-Turner times of transmission of 
P and § has been carried out. The data used were the residuals of 85 of the most 
fully observed earthquakes reported in the International Summary for 1923 to 1927. 
A statistical discussion has shown that the times for P require a reduction running 
up to 20s. at a distance of 32°-5, falling to 8s. from 60° to 70°, and rising again to 28s. 
at 107°-5. Similarly the present times for S require a reduction reaching 26s. at 
37°-5, falling to 8s. from 60° to 70°, and rising again nearly to 50s. at 107°-5. The 
standard errors of the results seem to indicate that the new times are correct within 
one or two seconds at all distances, apart from real variations as between different 
earthquakes. For P the agreement with a preliminary set of corrections given by 
Prof. Turner from the earthquakes of 1918 to 1922 is very good. Smoothing and 
interpolation have been carried out by Dr. L. J. Comrie. 
Prof. Turner always refrained from making a change in the tables used as a basis 
for the reductions in the International Summary on account of the probability that 
any new tables adopted would themselves be superseded in a few years; but there 
seem to be no grounds for further delay, and the errors of the present tables are a 
definite hindrance to understanding the results of the reductions for any individual 
earthquake, because they exceed the real differences due to the effects of local structure, 
which must be one of the next objects of seismological study. 
At distances between 10° and 20°, especially for 8, a complication was found 
which, for a time, produced a difficulty in interpretation. It is found that the true 
P and § are followed at intervals of about 8s. by other and somewhat larger pulses, 
which appear to have been reflected up and down once, twice, or oftener within the 
upper layers of the crust. These are shown most strikingly in Byerly’s study of the 
Montana Earthquake, and should provide a valuable check on other methods of 
