ON SEISMOLOGICAL INVESTIGATIONS. 245 



of magnetic and gyrocompasses, we have the means of observing temporary 

 disturbances of the former which might previously have passed unnoticed. 



In reporting the incident Commander Faulkner of H.M.S. Argus writes : — 



As both magnetic compasses were deflected similarly, it is doubtful whether a 

 vessel not fitted with gyrocompasses would have been aware of the disturbance. 

 Unfortunately no azimuths could be taken during the phenomenon. 



It is interesting to remark that the gyrocompasses are now good enough to be 

 trusted against the magnetic. In this connection the duration of the perturbation is 

 noteworthy. At ' 18-20 G.M.T.' the difference was 5° ; ' after 10 minutes the 

 difference . . . began to decrease until at 19-10 G.M.T. the standard compass course 

 became normal again — to be followed shortly after by the steering compass.' 



[The times as noted are of course earlier than the earthquake shock : what makes 

 the doubt is that they are noted as ' practically coincident with the earthquake which 

 destroyed the town of Corinth.'] 



Insfnuuental. 



The stations organised by Milne were equipped with his own simple undamped 

 seismograph, which was suitable for pioneer work. As time went on he realised the 

 need for damping, and asked Mr. J. J. Shaw to modify the instrument accordingly, 

 but he did not Uve to see the successful result. The ' Milne-Shaw ' seismograph is 

 the direct successor of the pioneer ' Milne,' and is thus in a special way connected 

 with the work of this committee. Mr. Shaw has suppUed (at the cost of construction 

 merely) many of these instruments for use in stations scattered over the world, some 

 of them in direct touch with this committee, others quite independent of it. The 

 work of construction has been carried out at his house (Sunnyside, Birmingham 

 Road, West Bromwich) either by himself or directly under his supervision. The 

 regrettable serious illness of Mr. Shaw interrupted this devoted work ; and though he 

 is now happily restored to health, the arrangements for resuming the work have not 

 yet been fuUy recovered. Nevertheless he is able to report as having been recently 

 instaUed : Melbourne, one component ; Harvard University, two components ; 

 Nizamiah Observatory, Hyderabad, the second component. Other machines have 

 been ordered, and the committee is able to hope that Mr. Shaw will find it now possible 

 to continue his important work of construction. 



International. 



The Comptes Rendus of the third meeting of the Seismological Section (at Prague, 

 1927, September 3-10) have been printed in a volume of 104+ 126 pages, the second 

 part containing accounts, reports presented to the Section, bibliography, &c. The 

 next meeting of the G. & G. Union has been fixed for 1930, August 18-25, at Stockholm. 



The work of this committee of the British Association was at first not international 

 in character, though world-wide. Milne's organisation of stations scattered over the 

 world, and armed with his simple pioneer seismograph, was in the first instance 

 confined to British stations, which reported to him at Shide. Their observations 

 were printed in the Committee's circulars, under the heading of each observatory, and 

 the collation of different observations for determining the epicentre and time of 

 occurrence was not printed in detail : the results simply were printed (and these for 

 considerable earthquakes only) for each year up to 1911. After Milne's death a 

 commencement was made of giving details for the ' large earthquakes ' from 1913 

 onwards ; smaller ones being gradually added until for the year 1917 the survey began 

 to approach completeness. By request of the Seismological Section at its meeting 

 in Rome in May 1922 the publication was made international, and the results for 1918 

 and following years have appeared as the International Seismological Summary. 

 Only a small portion of the whole cost, however, has been provided from international 

 funds. The cost of preparation has been borne partly by the B.A. subsidy of £100 a 

 year from the Caird Fund, partly by the generosity of Dr. Crombie, partly by the 

 Department of Scientific and Industrial Research, partly by the Royal Society, and 

 partly by the University of Oxford. The cost of printing (which might have been 

 provided from the international funds if the franc had maintained the value it had 

 in 1922) has been in itself larger than the international grant ; but the Royal Society 



