EARTH MOVEMENTS AT BURBINJUCK. 143 



EARTH MOVEMENTS at BURRINJUCK as recorded 

 by HORIZONTAL PENDULUM OBSERVATIONS. 



By Assistant-Professor Leo A. Cotton, m.a., d.Sc 



[Read before the Royal Society of N. S. Wales, August 3, lb2l J 



The investigations into the strength of the earth's crust 

 which are being carried out at Burrinjuck were undertaken 

 at the suggestion of Dr. W. G. Woolnough who was then 

 Assistant-Professor of Geology at the University of Sydney. 

 He pointed out that the construction of the Burrinjuck 

 Dam would offer a unique opportunity for testing the 

 behaviour of the earth's crust under a fluctuating load of 

 considerable magnitude. This project was supported by 

 the Australasian Association for the Advancement' of 

 Science which voted a preliminary grant to start the 

 investigation. Professor Woolnough was shortly after- 

 wards appointed to the Ohair of Geology at Perth and this 

 rendered it impossible for him to proceed with the investi- 

 gation. 



Some time later the Rev. Father Pigot S.J., who had 

 recently returned from Europe suggested to Professor 

 David that certain horizontal pendulums which he had 

 seen during his visit abroad would be eminently suitable 

 for the Burrinjuck research if they could be procured. 

 Professor David therefore approached Geheimrat Helmert 

 with a request for the loan of these instruments. The 

 request met with a very generous response, and Helmert, 

 with the co-operation of Hecker and Wolf, forwarded three 

 very valuable instruments for the purpose. These were 

 loaned to the Australasian Association for the Advance- 

 ment of Science, and were shipped free of charge. 



