442 T. W. E. DAVID. 
which the alkali had previously been leached by the rainfall of 
ages became re-impregnated with alkali. The remedy in Australia 
as in America was no doubt sub-drainage. 
Mr. J. C. H. Mingaye, F.c.s., M.A.I.M.E, Analyst and Assayer 
to the Department of Mines, in his valuable paper read before the 
Royal Society of N.S. Wales, June Ist, 1892, p. 100, has sug- 
gested the addition of a small quantity of gypsum to the soil 
previous to irrigation as a remedy against an excess of alkaline 
carbonates, the resulting sulphates being less hurtful to plant life. 
In Queensland Mr. R. L. Jack, F.a.s., the Government Geologist, 
and Mr. J. B. Henderson the Geren Hydraulic Engineer, 
had with remarkable foresight and courage spoken in no uncertain 
tones as to the comparatively limited extent of the artesian water 
supply, and he would like once more to emphasise the fact that 
in New South Wales also the supply was limited, so that possibly 
by the time that the quantity of water drawn from the artesian 
wells had been increased ten or twenty-fold, it would be found that 
the demand had overtaken the supply, that the annual outflow had 
equalled the annual intake of rain water into the artesian water 
beds. It was daily becoming more urgent that the pulse of the 
artesian water supply should be felt with a view of ascertaining 
whether the hydraulic grade was already being lowered or not by 
the existing wells. This end would probably be best attained by 
the application of pressure gauges to all the available artesian 
bores. The results of accurate measurements taken by means of 
these gauges would probably not only be of considerable economic 
importance, but would also, as stated by Mr. Whitfeld, throw 
more light on the questions (1.) as to whether the supply was 
hydrostatic or hydraulic; (2.) as to whether it was directly 
dependent on the amount of rainfall, and if so as to how long a 
period was necessary for the percolation of the rain from the 
intake to the artesian wells, and (3.) as to the principal channels, 
if any, through which the artesian water flowed. The application 
of pressure gauges and the desirability of locating new bores along 
axes of anticlinal curves were the two points to which he hoped 
attention might in future be specially directed. 
