270 THE PHYSICAL GEOGRAPHY OF AUSTRALIA. 



Dividing* Range. In these districts there is a regular wet and dry sea- 

 son — the former occurring in the months of December, January, and 

 February, when the atmosphere is heavily laden with moisture and the 

 shade temperature, of from 80 to 90 degrees, exceedingly oppressive. 

 During this period there is a prevailing northeast wind, which changes 

 to southeast and continues in that quarter throughout the remaining 

 nine months of the year. In the Oardwell district the tropical scrubs 

 sometimes ascend the ranges to a height of over 2,000 feet, where the 

 temperature is lower than that to which they properly belong, but such 

 cases only occur where the volcanic soils are exceptionally rich. In 

 Arnhem's Land, or all that high table-land portion of the Northern 

 Territory of South Australia north of the sixteenth parallel, the annual 

 rainfall averages about 60 inches, and is more equally and generally 

 distributed than in any other part of the continent; the climate is, of 

 course, tropical, but the mornings and evenings are generally cool, and 

 the usual discomforts of the moist atmosphere of the low lying eastern 

 and northern coast lands are not felt here on the dry upland zone of 

 the plateau. A remarkable feature of the prevailing Australian cli- 

 mate is found in the rapidly diminishing rainfall after crossing the 

 Great Dividing Range of the southern and eastern cordillera. There 

 is an immense belt of country comprising the western plains of New 

 South Wales and Queensland; Cape York Peninsula; the whole of the 

 country bordering upon and extending far south from the head of the 

 Gulf of Carpentaria; most of the southern portion of the Northern 

 Territory of South Australia, and the Glenelg and Kimberley districts 

 of the western portion of the continent, where the average annual 

 rainfall does not exceed from 10 to 30 inches. Except in the extreme 

 southwest corner of Australia, where the isopluvoise lines of 20 and 30 

 inches are fairly well established, the rainfall of the western division 

 is very scanty, being limited to a narrow belt along the seaboard, where 

 it only averages from 10 to 20 inches. In the Murchison and Gascoyne 

 districts extremely heavy dews occur, which, no doubt, compensate 'to 

 some extent for the lack of an adequate rainfall. In the northern part 

 of western Australia the wet season commences in December and 

 usually ends in March, and it is during this period the destructive 

 cyclonic storms are experienced. These are of the true equatorial type 

 and move along with enormous velocity, often causing great destruction 

 to property and not infrequently loss of life. The wet season of the 

 southern district is from April till October, during which time most of 

 the annual rainfall is recorded. The climate here is temperate and in 

 every respect congenial to Europeans; fruits and agricultural produce 

 are plentiful, and the forests yield an abundance of very valuable tim- 

 bers. In the Kimberley district the heat of the summer months is 

 intense, but during the cool season the climate is agreeable. In some 

 of the northern districts the temperature, although very high, is not by 

 any means inimical to health, as the atmosphere is remarkably free 



