48 



PROCEEDINGS OF SECTION A. 



damping. The latter has the advantage of comparative cheap- 

 ness. The Riverview Observatory is fitted with a Wiechert 

 Astatic pendulum and with a Mainka Bifillar Conical Pendulum; 

 and I take this opportunity of welcoming to the ranks of seismo- 

 logical workers in Australasia the Rev. E. F. Pigot, S.J., Director 

 of the Observatory. 



SYDNEY OBSERVATORY. 

 W. C. GRAHAM, Observer. 



With the exception of three instances when the clock of the 

 Seismograph, a Milne horizontal pendulum, was stopped owing to 

 flaws in the sensitised paper, the instrument has been continually 

 recording during the years 1909 and 1910. The disturbances have 

 greatly outnumbered those of the two preceding years. Whereas, 

 during the years 1907 and 1908 ninety-six and ninety tremors 

 respectively were recorded, in 1909 one hundred and fifty-eight, 

 and in 1910 one hundred and sixty-three tremors were " trapped " 

 by the Sydney Observatory Seismograph. 



Classifying them according to their intensity, they are as 

 follow :— 1909. 



