ARID PORTIONS OF SOUTH AUSTRALIA. 99 



CLIMATE. 



The mean annual rainfall for Quorn is 13.82 inches. The highest 

 precipitation recorded was 25.77 and the least 7.43 inches. The mean, 

 maximum, and minimum amounts of rain for each month are given 

 in table 2. 



It will be seen from table 2 that Quorn is in the belt of winter 

 rains. Beginning to fall in appreciable amount in the last month of 

 autumn, the rains are maintained through the winter and until well 

 into the spring, only about 30 per cent falling during the warm season. 

 The mean rainfall of the latter is 4.18 inches. This is very little more 

 than that for the same month at Copley, which is 3.82 inches, or 45.4 

 per cent of the whole. Therefore, the rainfall of the warm season at 

 Quorn is relatively and actually small in amount, and possibly this 

 gives the xerophytic stamp to the flora of the region, whereas the 

 relatively, as well as actually, large winter rainfall makes possible 

 an abundant vegetation. Further, it is this which makes wheat- 

 growing without irrigation possible in the region. 



Although the rainfall at Quorn is fairly large, it has certain char- 

 acteristics which show that the region is in fact semi-arid. The ratio 

 of driest to wettest years is 1 to 3.4. In a humid region, as for example 

 at Hobart, Tasmania, this ratio is much less, being 1 to 1.8. At Quorn 

 the year having the greatest precipitation (1889) followed that with 

 the least precipitation. However, there may be a series of dry or wet 

 years when successive years would show a great consistency. 



The rainfall on the Willochra plain, as would be expected, is less than 

 at Quorn. For example, at Bruce, about 12 miles southeast of Quorn 

 and on the western side of the plain, the annual precipitation is 9.88 

 inches. In closer relationship to the high mountains, as at Mount 

 Brown, Melrose, and Wilmington, the precipitation is greater than at 

 Quorn. The mean for the three places is 17.23, 23.1, and 18.23 inches, 

 respectively. The rainfall on the upper slopes of Mount Brown and 

 Mount Remarkable must be considerably more than that recorded 

 for stations at their base. 



I have not seen data on the temperature at Quorn, nor for any sta- 

 tion near, but the temperature at Yongala, distant about 65 miles, 

 may be useful as illustrating certain main features of the temperature 

 conditions of the general region. The rainfall at Yongala is almost 

 the same in amount as at Quorn, and the place has a considerable 

 elevation. In a sense, therefore, the two are comparable. The fol- 

 lowing is a summary of the conditions at Yongala : Mean maximum, 

 69.2; mean minimum, 46; mean temperature, 59.6; highest maxi- 

 mum, 107.6; lowest minimum, 19.8 F. The mean diurnal range is 

 24.9 and the greatest daily range recorded at the station is 50.7 F. 



When the preceding temperature data are compared with those 

 for Farina, as representing Copley, for example, it is seen that the 



