PROBLEMS OF THE ARTESIAN WATER SUPPLY OP AUSTRALIA. 115 



lines referred to by Gregory. It is very much to the credit 

 of the hydraulic engineers of the three States that they 

 have accomplished so much in the face of great difficulties, 

 but Mr. J. B. Henderson informs me that most of the levels 

 of the Queensland bores have been taken by aneroid obser- 

 vation, and although Mr. J. A. Griffiths (Mr. Henderson's 

 assistant) performed this work with the greatest care, it 

 is impossible that the same accuracy could have been 

 obtained as if the dumpy level had been employed. Until, 

 therefore, the work has been checked, and carried much 

 nearer to completion, it would be futile to attempt to 

 explain the inconsistencies which appear to exist in the 

 published maps. It may be stated that similar anomalies 

 in regard to pressure have been noticed in the artesian 

 wells of the Dakota basin, and they have not been definitely 

 accounted for, though several possible explanations have 

 been advanced. 1 



It is understood that the isopotential work in South 

 Australia has been performed with the aid of the spirit 

 level, as has that in New South Wales, and the fact (recorded 

 by Professor Gregory) 2 that Mr. J. W. Jones successfully 

 predicted the height to which the water would rise in some 

 localities, appears to be incapable of explanation except on 

 the assumption that the flowing wells are caused by 

 hydraulic pressure. 



One statement of Professor Gregory's in regard to the 

 subject of isopotentials requires to be amended. He says 8 

 that in New South Wales there is no evidence of regular 

 decrease of pressure towards the west ; but a glance at the 

 map published by Mr. Allan 4 will show that the hydraulic 



1 Preliminary Eeport on Artesian Waters of a Portion of the Dakotas, 

 N. H. Darton, Seventeenth Ann. Eept. U.S. Geol. Sur., 1895-6, pp. 668-9. 



2 Dead Heart of Australia, p. 293. 3 Ibid., p. 311. 



4 The Drought Antidote for the North-west, New South Wales, Percy 

 Allan, 1906, pp. 44. 45. 



