PROBLEMS OF THE ARTESIAN WATER SUPPLY OF AUSTRALIA. 107 



world. But its incorrectness can be easily demonstrated 

 by extracts from Professor Gregory's own book. He quotes 1 

 from Box's Hydraulics to show that a 1 incli pipe discharg- 

 ing a gallon of water per minute will lose, owing to friction, 

 700 feet of head in a distance of 100 miles, and he asserts 

 that if the water were flowing through sand instead of a 

 pipe it would lose very much more head. He had pre- 

 viously 2 referred to the Grenelle Bore, in the Paris basin, 

 as an example of a flowing well in which the ascent of the 

 water is really due to hydrostatic pressure. Now accord- 

 ing to Prestwich :J and D'Aubree 4 the width of the Paris 

 basin, or, in other words the distance between the intake- 

 beds at Champagne and the Grenelle Bore, is just about 

 100 miles. Therefore if the water flowed between those 

 two places through a 1 inch pipe instead of through the 

 Lower Grcensands, there would be a loss of 700 feet of head 

 in the distance, and (according to Gregory) as the water 

 actually flows through sand, the loss of head should be very 

 much more. But Prestwich states 5 that the difference in 

 altitude between the Oliampagne Hills and the Grenelle 

 Bore only averages about 261 feet : therefore the water at 

 Grenelle should not rise within at least 439 feet of the sur- 

 face, whereas it actually rises 120 feet above the surface, 

 or would if it were allowed to rise in an open pipe. It 

 appears also that the loss of head in this instance is only 

 about 136 feet (instead of 700 feet) in 100 miles. 



Rate of Flow of Underground Waters.— It is clear there- 

 fore that either the flowing bore at Grenelle is not caused 

 by hydrostatic pressure, or that the loss of head in the 

 case of water traversing porous rocks is nothing like 700 

 feet in 100 miles. Let us enquire into the latter statement. 



1 Ibid., p. 303. 2 Ibid., p. 282. 



3 Prestwich, Quart. Journ. Geol. Soc., 1872, xxviii., p. lix. 

 1 D'Aubree, Les Eaux Souterraines, Vol. i., 1887, p. 209. 

 5 Op. tit. 



