98 E. 2\ Quayle ; 



Evidences from Decennial Rainfall Maps. 



In order that the decade 1910-1919 should not have to carry 

 the whole burden of proof that rainfall is affected by changes in 

 the surface of the country, I plotted the rainfall departure in 

 similar fashion for each of the three decades, making up the 

 standard period. The results are most interesting and quite in 

 accordance with the theory. 



1885-1894. Over the inland areas of South-eastern AustraUa, 

 or east from a line joining Spencer Gulf, Lake Torrens and Lake 

 Eyre, this was a remarkably wet decade. While this helped to 

 fill the lakes in South Australia, and increased the floodings of 

 the Murray and its tributaries, thus producing evaporation areas 

 and increasing the rainfall in the favoured areas, the generality 

 of the abundant rainfall, which was largely of direct tropical 

 origin, tended to obliterate these local preferences. We can 

 look, therefore, for smaller percentage gains over the areas 

 usually favoured. This shows up quite well on the map. The 

 following strips of country showed less gain than the country 

 on either s:ide : (i) Along the Murrumbidgee from its junction 

 with the Lachlan, almost up to Narrandera; (2) From Yarra- 

 wonga to Deniliquin and Piangil, or along the upper Murray 

 and Edwards ; (3) From Shepparton, along the Murray to Went- 

 worth ; (4) From Wentworth to Lake Torrens. As regards the 

 river areas, this tends to confirm the reality of the rainfall 

 increases shown by the isohyets on the average annual rainfall 

 map to obtain along the Murray and the principal streams 

 through the Western Riverina. When the map was constructed, 

 in 1910, this was regarded as a freak result. The actual percent- 

 age departures from average are as follows. Beginning with the 

 plain country north of the Murrumbidgee, and ending with the 

 Victorian plain country south from the Murray River we get : 

 Plains (northern) +28, Murrumbidgee River 4-19, Plain +24^ 

 Edwards and Murray River (upper) +20, Plains +2^, Murray 

 River (lower) -f-17, Plains (Victoria) +24. 



For the decade the greatest percentage increases are over the 

 north-west and central plain country of New South Wales, where 

 some reach 40 per cent. The dominantly tropical origin of the 

 rains is obvious. 



Stations along the Darling from Pooncarie to Wilcannia show 

 very consistent increases of over 30 per cent., which may have 



