448 L. A. COTTON. 



SOME GEO-PHYSIOAL OBSERVATIONS AT 

 BURRINJUOK. 



By Leo A. Cotton, b.a., b.Sc, 



Acting Professor of Geology, University of Sydney. 

 With Plate LXII, and Three Text-figures. 



[Read before the Royal Society of N. S. Wales, December 1, 1915. ,] 



The problems relating to the strength of the earth's crust 

 present an attractive field of investigation alike to the 

 mathematician, the physicist and the geologist. Such 

 investigators as Fisher, Darwin and Love have given atten- 

 tion to the mathematical aspects of the question. In the 

 realm of physics such men as Airy, Hecker and Hayford 

 have respectively examined the problems from the stand- 

 points of astronomy, seismology and geodesy. Among 

 geologists, such names as Gilbert, Ohamberlin and Barrell 

 are associated with these problems. 



In this communication it is desired to present a brief 

 preliminary account of a new experimental line of investi- 

 gation in this branch of science. 



The State Government of New South Wales have under- 

 taken a large irrigation scheme, x the reservoir for which 

 is being constructed on the Murrumbidgee River at Burrin- 

 juck. The dam is to have a maximum height of 236 feet, 

 and the water to be stored is estimated at 33,000,000,000 

 cubic feet, a greater volume than the water contained in 

 Sydney Harbour. The impounding of such a large mass of 

 water, having such a great depth, will impose a certain 

 strain on the earth's crust. 



1 For a brief account of this work see Handbook for New South Wales, 

 published for members of the British Association for the Advancement 

 of Science, 1914, pages 146, 147. 



