170 ALEX. L. DU TOIT. 



How large is the amount of carbon dioxide held com- 

 bined is perhaps not fully realised. While the Oa and Mg 

 salts are in the bi-carbonate form, that of Na is either 

 normal or acid; from statements made by Mingaye and 

 Symmonds it appears that in New South Wales at least, 

 the bi-carbonate state is either closely or fully attained. 

 Taking the general analysis of the waters, the combined 

 0O 2 per gallon would range from a minimum of nearly 20 

 grains to a maximum of about 80, and the average water 

 may be reckoned to carry about 40 grains, or nearly three 

 tons per million gallons. When comparisons are made with 

 river, ground or artesian water of undoubted meteoric 

 origin, it will be found firstly, that carbonates are rarely 

 present in such high proportions, or, if so, on a large scale, 

 and secondly, that, when they do occur, they consist almost 

 entirely of those of Oa and Mg, and that sodic chloride is 

 invariably present in relatively high amount and frequently 

 sulphates also. 



As to the quantity of 00 2 that could be derived from the 

 organic matter in the rocks through the action of free 

 oxygen of atmospheric origin dissolved in the entering 

 water, it can readily be shown from the known solubility 

 of the latter gas, that, under the conditions obtaining over 

 the intake area, this would amount to not more than from 

 4 to 5 grains per gallon at the most. That a little oxygen 

 may be left unused in the process is shown by the rare 

 occurrence of this element in a few of the bores in the 

 Ooonamble district. 



Of considerable importance is the fact shown by Fawsitt 

 and Symmonds, that in New South Wales — and probably 

 this will be the case elsewhere — free OOg is confined to the 

 lower levels of such bores as contain it, and this, as Sym- 

 monds has logically argued, points strongly to a subter- 

 ranean source for some of the gas at least. 



