102 E, T. Quayle: 



Need for a National Policy. 



The other is that every facility should be given to settlers to 

 make payable use of our remoter inland areas, even to the extent 

 of national financial, and other sacrifices, recognising that this 

 occupation of the interior is a sure way of ameliorating the 

 climate for the rest of the continent or, at all events, for all those 

 areas in lee of the outpost belt. Obvious methods are, of course, 

 the adoption of some zone system for railway fares and freights, 

 and the establishment of the greatest water schemes the conti- 

 nent is capable of. The addition of four or five inches of rain to 

 the average annual rainfall of our dry areas, especially if the 

 addition were maintained during drought periods, would mean 

 multiplying their value by 20 at least. 



It is evident, too, that the further inland the water can be 

 stored or utilised, the more extensive will the area benefited 

 <:Hmatically be. 



Tropical Origin of Inland Rains. 



Keeping Lake Torrens full would evidently help to keep Lake 

 Prome full also, the latter draining a very large proportion of 

 the country benefiting. If we consider the origin of these inland 

 rains, and the processes at work in their production, this state- 

 ment will prove not so extravagant as it seems at first sight. 

 The mapping of the daily departure from normal of the minimum 

 temperatures at all stations over the northern half of the con- 

 tinent shows that practically all the inland rains are of tropical 

 •origin. That is, rain never falls, say, in the neighborhood of 

 Lake Frome without previous evidence of a drift towards this 

 region of a body of relatively warm, moist air from some 

 northerly point, most often, presumably, from the north-west. 

 Condensation is usually the result of latitudinal cooling, and may 

 take place without the assistance of any storm developments, 

 though it most often occurs in the north-eastern front of "south- 

 ern" disturbances which naturally accelerate the southward 

 drift of the air in front of their troughs. It is occasionally helped 

 too by what appears to be displacement upwards of this warm 

 air by the cold, dry air of an anticyclonic system moving inland 

 from some point south of west. But whatever the outside 

 accelerating influences, it is certain that evaporation from any 

 considerable body of water in the path of this southward-moving 

 air will have a powerful efifect in deciding where and when 

 precipitation shall begin. Assuming, say, that we have, as these 



