122 E. T. Quayle: 



In this latter respect Southern Australia enjoys a position dif- 

 ferent from that of some almost rainless countries, such as 

 Egypt, where, in spite of irrigation on a grand scale, no marked 

 increase of rainfall is observed. When the upper air has a 

 humidity consistently much below that necessary for rainfall, 

 the provision of any limited evaporation area is not likely to bring 

 it up to the point of rain production, but in Southern Australia 

 the upper air is sufficiently humid for a little rain with the pas- 

 sage of almost every Antarctic disturbance. This may help to 

 explain the marked assistance which this paper suggests evapora- 

 tion areas to have towards rainfall production. In the very 

 dry central portion of the continent it might be much more dif 

 ficult to trace such effects. 



(2) By Irrigation. 



In the south-eastern portion of the continent fairly extensive- 

 schemes have been brought to partial fruition, the chief of which 

 are the fruit-growing areas at Mildura, Merbein, Renmark (in 

 South Australia), and Curlwaa (in New South Wales), all near 

 the extreme north-west corner of Victoria, and probably giving 

 some 30,000 acres of fully irrigated lands. Then, upstream, along" 

 the Murray, are areas irrigated for lucerne and fruit at or near 

 Swan Hill, Cohuna, Koondrook, etc., aggregating in 1912-13 some 

 90,000 acres. From the Goulburn some 60,000 acres more were 

 irrigated in the same year. As most of this area would be rather 

 dry in average years — certainly the 120,000 acres directly irri- 

 gated from the Murray and Loddon would be — there must be 

 considerable evaporation from these, which would not be avail- 

 able under purely natural conditions. To these are being added 

 considerable areas in Victoria, and the comparatively large Mur- 

 rumbidgee irrigation areas in New South Wales supplied from 

 the Burrinjuck reservoir. 



These schemes have all been undertaken without reckoning 

 upon any climatological improvement as the result. But it is 

 probable that even from that point of view, we shall have interest 

 for our money, and not simple, but compound, interest. If the 

 rainfalls on the eastern and western shores of Spencer's Gulf and. 

 Port Phillip Bay are any guide, a 20 mile expanse of water 

 may increase the rainfall by several inches, and, as the evapora- 

 tion from irrigated areas is at least equal to that from ocean 

 surfaces, and the irrigated areas are already large enough, stations- 



