NATURE VHRSUS THE AUSTRALIAN. 
One’ often hears that agriculture may be found profitable in the 
interior where the average rainfall is 10 inches, because wheat can ve 
grown with such a rainfall in the Mallee or in the northern region of 
Western Australia. As a matter of fact, none of the Mallee is below 
10 inches—and I have never been able to find a region in Western 
Australia below 10 inches where wheat is grown at all regularly. 
If the rainfall at the right season exceeds 11 or 12 inches, and 
is reliable, well and good. But, as I shall now proceed to show, the 
greater part of arid Australia is cursed, not only by a low rainfall, but 
by a very uncertain one. By a method of reckoning, which I have 
explained elsewhere,* I have drawn up the reliability isopletht shown 
in Fig. C. 
The most variable region in moat is around Onslow (W.A.). 
The best is around Perth, in the same State. The reason for the 
success in wheat in the south-west corner (Swanland) is shown at a 
glance. All the arid country (under 10 inches per year), except in 
Swanland and along the Trans-Australian Railway, has a variability 
exceeding 20 per cent. of its average total. Moreover, a great deal of 
the country, with better rainfall—especially to the south of the Gulf of 
Carpentaria—has also a very erratic rainfall. Thus the Barkly Table- 
land seems to be a very unpromising agricultural region, im spite of its 
average of 15 or 20 inches a year. 
As regards future prospects of Juialainanis as based on rainfall, we 
may subdivide Australia into seven regions. In the following table the 
régions are arranged approximately in order of value. (See Fig. C.) 
Class. 3 Sub-class. Chief Localities. 
: = 
1, Uniform ave .. | With winter maximum ~. | Riverina, Victoria, ‘Tas- 
mania ; Z 
2. is ee .. | With summer maximum .. | Eastern Queensland, north- 
east of New South Wales 
3. Seasonal, but reliable .. | Moderate winterrain .. | ‘‘Swanland ” (Western Aus- 
tralia) 
4, 43 ” .. | Summerrain .. .. | Kimberley and Northern 
; Territory 
5. » » +. | Arid winter rain . .. | Coolgardie to Broken Hill — 
ES ea a a mi , 
6. Erratic a .. | Summer only .. .. | Pilbarra, Macdonnells 
18s ier . .. | Arid only bys .. | Central Australia 
Our agricultural at pastoral production can be classified in terms 
of these regions. ‘Thus all the important timber areas are confined to 
* See Fig. 125 in Australian Meteorology, 1920. (Oxford University Press.) 
} Isopleth, a term akin to contour; i.é., a line through localities > xperiencing the same conditions. 
467 
