SCIENCE AND INDUSTRY. 
of our continent. Every one knows that our fertile areas are disposed 
like a green garland around the arid interior. The wreath is broken 
on the west coast, where the out-flowing trade winds have dried a belt 
from Shark Bay to North-west Cape. It is very narrow along the 
Bight, and appears to be very broad along our northern coasts; and, of 
course, the belt of pasture and forests is best developed down the eastern 
coast. 
If we watch how the rain belts vary from month to month we find 
that they march south with the sun. In mid-summer the northern belt 
(fed by tropical low-pressure systems) extends to Alice Springs. Tr 
winter the southern belt (controlled partly by Antarctic systems) moves 
north to Port Augusta, or farther. (See Fig. OC.) 
Hence there is a drought in the north during the colder months, and 
a drought in the south during the warmer months. ‘This distinction is 
perhaps more important than the season of the rain, as we shall see 
later. 
In the centre and west centre the rainfall is very low, and is due to 
erratic thunderstorms. In the east special coastal storms favour the 
littoral at most times of the year, especially in autumn; and in Queens- 
land, as we have seen, the trade wind brings rain almost all the year 
round. 
Hence our chief rainfall regions are four in number:—The uniform 
rain in the east and south-east; the winter drought region in the 
north; the summer drought region in the south and south-west; the 
arid region in the centre and central west coast. All our primary indus- 
tries—other than those of mining—are determined by these conditions, 
but one further feature remains to be discussed. 
It is a truism that if the rainfall were only reliable it would not 
matter so much if it were comparatively small in amount. By long 
experience farmers have learnt that in the Western Australian wheat 
belt a lower rainfall will suffice than in western New South Wales. 
Now that our records are fairly complete in many parts of the Com- 
monwealth it is possible to study this aspect scientifically. 
Consider the following table, where the same months in consecutive 
years have been taken at the places named. 
Unrevraste RAINrALt. 
Onslow (Western Australia) .. | April, 1900 .. 11:0” | May, 1900 .. 10-5” 
peel OU liner 0 are O0 Tene OED a 
(April Average, 0°9”) (May Average, 1°5”) 
Borroloola (Northern Territory). . | March, 1899.. 29°0” | Feb., 1896 .. 21:4” 
Smet U00 cee 2 210 B78, WaLS0 7a ee dee 
(March Average, 6:0”) (Feb. Average, 7°4”) - 
Charlotte Waters (South Australia) March, 1908 .. 5:0” | Jan., 1877 oo ; 
j » 150 G Septem 0 a py AVES | ce 
<, (March Average, 0°7”) (Jan. Average, 0°8”) 
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