42 



SBISMOLOGICAL REPORTS. 



desirability of such an arrangement, and, as some of the 

 Australian Observatories, whose records are svipplied to 

 Professor Milne, have been asked to co-operate with the 

 other abovementioned association, it would be expedient 

 for us to know more clearly than we know at present 

 the exact relations and objects of these two bodies. 



I would suggest that the Council be recommended to take steps 

 with the object of obtaining definite information and opinions from 

 the proper authorities in England and Germany on this question. 



SEISMOLOGICAL REPORT FROM THE SYDNEY OBSERVATORY'. 



Sydney Observatory, 23rd December, 1908. 



Dear Sir, — I trust you will overlook ni}^ seeming dilatoriness in 

 answering your two letters, dated 11th October, 1908, in which you 

 ask for a brief account of the seismological and magnetical work 

 carried on at the Sydney Observatory since January, 1907. Mj 

 excuse is that I have delayed matters so long in order to be able to 

 supply you with records quite up to date. With regard to seismology, 

 with the exception of four short stoppages, extending over about a 

 day at each period, our Milne siesmograph has been recording con- 

 tinuously. During the year 1 907 ninety-six tremors were experienced, 

 and, classing them in order of intensity, they are as follows : — 



1 tremor over 15 m/m amplitude, 18th December 



■ 1% 



. 2% 



• 1% 



• 30/, 



• 2% 

 ■ 6% 



• 14% 

 . 71% 



16 tremors. 

 11 



9 

 13 



9 



3 



From 1st January to 12th December, 1908, eighty-two tremoi^e 

 have been recorded on our instrument, as under : — 



2 tremors between 6 and 7 m/m amplitude ... ... 2% 



1 

 1 

 1 

 3 

 U 

 60 



less than 1 m/m 



1% 

 1% 

 1% 

 4% 

 17% 

 73% 



