254 REPORTS ON THE STATE OF SCIENCE, ETC. 



clearer, and it will be possible for the Committee at an early meeting to 

 consider it fully. 



Immediate anxiety has been avoided by the action of the Government Grant 

 Board in renewing its contribution of 300?. for the present year at the meeting 

 in March 1922. 



Instrumental. 



The Milne-Shaw seismograph in the basement of the Clarendon Laboratory 

 at Oxford has worked well throughout the year. A most curious disturbance 

 to which the trace was liable very occasionally, and of which for some time 

 no explanation could be assigned, has now been identified as due to pressure 

 on the floor above at a particular point, transmitted by a pillar between the 

 two floors ; but further experiments will be made. 



Miniature copies of films, as suggested in the last report, have been received 

 from Edinburgh, Helwan, and one or two other observatories, and found very 

 useful. Attention is again called to them in the hope that other observatories 

 will send such copies at their convenience. 



During the year Milne-Shaw machines have been despatched to Toronto (2) 

 and Victoria, B.C. (2). In addition the opportunity of the eclipse expedition 

 to Christmas Island was taken, with the approval of the Astronomer Royal, to 

 send a Milne-Shaw equipment in the care of the eclipse observers, who will 

 be on the island for some months. They were to set up the instrument as soon 

 as the immediate requirements of the eclipse preparations were sufficiently 

 satisfied, and to take records for the duration of their stay on the island. If 

 a competent person could be found to take charge of the instrument after their 

 departure it was to be left in his care ; if not, to be brought home again. The 

 outcome of this experiment is awaited with considerable interest, for the 

 neighbourhood is an important one. 



Bulletins and Tables. 



The bulletins for January-February and for March-April, 1917, have been 

 published. May-June was sent to the printer in May of last year, but owing 

 to a shortage of suitable type (now remedied) it was ultimately decided to print 

 May alone. It is now being printed off, and will shortly be distributed. June 

 (1917) has been received in proof ; July and August are ready for the printer, 

 September and October nearly ready. Two reasons have contributed to this 

 further delay (for in order to catch up arrears we must print in one year not 

 less than twelve months but more). The first, the continued dropping in of 

 new material — e.g. results for Vieques and Cheltenham in 1917 were only 

 received a few days ago. It is true they were themselves in printed form, and 

 printing has suffered in many ways lately ; but the opportunity may be taken 

 to repeat the request to observatories to send results in MS. as soon as possible, 

 so that they may be collated with others. Further, it may be remarked that 

 when copies of results are manifolded sometimes almost illegible examples are 

 received. It would be a real kindness, and facilitate work, if poor copies could 

 be omitted or doubtful figures rectified by hand. 



The second reason originates in the gradual development of the work by 

 the inclusion of smaller earthquakes. It is naturally these which give most 

 trouble in identification, hut it was thought desirable to make trial whether 

 their inclusion could be managed with our present facilities, and it has been 

 concluded from experience that the effort should be made. It will suffice to 

 refer to the paragraph on Periodicity as evidence of the value of these smaller 

 earthquakes. 



Depth of Focus. 



On March 3, 1922, the subject chosen for the Geophysical meeting of the Royal 

 Astronomical Society was the depth of earthquake foci, with special reference 

 to Mr. G. W, Walker's suggestion of a considerable depth — comparable with 

 0.2 of the earth's radius. The contribution made from this Committee was 

 based on the study of the arrival of the first waves at the Antipodes, for which 

 the standard formula 



20ra. 17s. — (180-A)2 x 0= -0235 



I 



