296 THE FUTURE OF ARID LANDS 
20 
Total rainfall (inches) 
o) 
10 20 3I 
January February 
Figure 5. The total rainfall of Sydney for each day in January over 
the period 1859-1952. 
One’s first reaction is that these variations are due to statistical 
fluctuations. If they arise from purely random causes they would 
normally smooth out as records of more and more rain gages are 
totaled. As a next step Figure 6 shows the January rainfall for 
20 stations in the state of New South Wales, all more than 100 
miles from Sydney. The peaks are still present and, furthermore, 
they occur on precisely the same dates as those in the Sydney 
record. It begins to appear, therefore, that this is a real phenom- 
enon and the rainfall in this area and for this particular period 
300 
G 
s 13 oe 
£200 ° \ 
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lo} ° \ 
fe WY \ s Ip Ne i * VA 
5 
£100 r 
o 
+ 
i 
[ake [eae eee eee P| vee Si 
O 10 20 31 
Janvary February 
Figure 6. The January rainfall of twenty stations in New South 
Wales for the period 1890-1946. 
