120 R. G. Thomas: 



area from the closer settlement country where more intensive 

 farming is possible. The lo-inch line of winter rainfall has- 

 usually been regarded as the safe limit for wheat growing, but 

 in South Australia and Victoria wheat is grown over a very 

 considerable area inside this line, extending to, and even passing 

 the 7.5-inch line. The wheat-growing districts about Edeowie 

 and Morgan in South Australia, and immediately south of 

 Mildura in Victoria, are beyond the 7.5-inch Une of winter 

 rainfall; while between the 10 and 7.5-inch lines are the older 

 settled Mallee districts of Veitch, Ouyen and Swan Hill, where 

 wheat growing has been an established and successful industry 

 for over 10 years. It can be fairly assumed then that country 

 having a winter rainfall of somewhat under 7.5 inches, of relia- 

 bility equal to that in the areas indicated, and an average tem- 

 perature not greatly above that of these areas, is capable of 

 growing wheat under our present methods of cultivation and 

 economic conditions of price of wheat, land and labour. In New 

 South Wales the lo-inch line has not yet been passed, and it 

 would seem that in the northern portion of the State it does 

 indicate the probable limit of the wheat belt. The greater varia- 

 bility of the rainfall, and the higher temperature, causing 

 increased loss by evaporation, make a given average rainfall less 

 efficient in crop production here than a similar amount in the 

 cooler and more reliable rainfall areas in the southern portion 

 of the State. 



It is difficult, indeed, to indicate the ultimate inland limitS' 

 of the wheat belt in Australia, for with improved, drought- 

 resistant varieties, and better methods of cultivation, new areas 

 are being brought under crop which but a few years previously 

 it was thought impossible to successfully cultivate. This in- 

 creasing efficiency will, it is hoped, continue. But even with our 

 present knowledge there is ample room for expansion before 

 what may be termed the probable limits of the wheat belt in the 

 more immediate future are reached. The line shown thus: 

 — X — X — , is an arbitrary line, indicating what appears, froiTE 

 climatic considerations, to be such probable limit, and it is seen 

 to enclose immense tracts' beyond the present limits of develop- 

 ment. Commencing on the lo-inch winter rainfall line, south 

 of Shark's Bay, W.A., where the variability of the rainfall, is too 

 great to warrant an extension of the 7.5-inch line, it passes west 

 beyond the 7.5 line, as the more reliable rainfall along the 



