ARID PORTIONS OF SOUTH AUSTRALIA. 67 



the plain was wetted to a depth of 8 to 9 cm. The observations were 

 repeated a few days later with substantially the same results. In both 

 instances the rains were followed by drying weather, so that a large 

 percentage of the moisture taken into the soil must have been lost 

 quickly by evaporation. It was assumed that had the rainfall been 

 25 per cent less, the penetration would also have been very much less, 

 and the amount of water lost by evaporation would bave been rela- 

 tively greater with respect to the amount recorded. Therefore, 

 under such conditions there would be very little, if any, available for 

 the use of plants, more especially for the use of perennials. However, 

 as will be shown below, there is no doubt that, given favorable soil 

 conditions, a rain amounting to 0.20 inch penetrates the soil suffi- 

 ciently to moisten the horizon occupied by the roots of many annuals 

 and also by a portion of the horizontal roots of certain perennials. 



TEMPERATURE. 



The temperature records for Copley were not examined by me, but 

 the Commonwealth Bureau of Meteorology very kindly supplied the 

 records for Farina, 40 miles farther north, which have been accepted 

 as illustrating the conditions at Copley. A summary of these records 

 for Farina has been given in table 7, which shows that the highest 

 shade temperature reported for the station, for a period of 28 years, 

 was 119 F. The absolute minimum was 25.3 F. The annual range 

 may be considerable; for example, in 1912 the minimum reported 

 was 27.3 F. and the maximum was 118 F., a total range of 90.7 F. 

 During the same year the mean daily range was 18.6 F. and the maxi- 

 mum range observed during the course of one day was 53 F. The 

 mean yearly temperature at Farina is more than 10 F. below that at 

 William Creek, as representing Oodnadatta, and it is nearly 4 higher 

 than that at Adelaide. For other details, reference can be had to 



table 7. 



VEGETATION OF THE COPLEY REGION. 



The most striking features of the flora of the lowlands between 

 Marree (Hergott Springs) and Copley are its abundance and the fact 

 that it is practically all of one type, namely, halophytes. Viewed from 

 some distance, the relatively slight individuality of the species is lost 

 and the plains appear closely covered with a uniform growth. In and 

 along washes and on the slopes of the hills, however, the vegetation is 

 generally composed of sclerophyllous shrubs and trees which vary 

 greatly in size, form, and occurrence. Even at this day, and in spite 

 of the heavy demands of whatever nature made on the native vegeta- 

 tion by the white inhabitants, there is a remarkable wealth of plants, 

 not only as regards species but also as to number of individuals; and 

 it is to be remembered that the rainfall of the region is by no means 

 heavy. At Marree it is 6.08 inches and at Copley 8.40 inches, of 



