PHYSIOGRAPHY OP THE AUSTRALIAN ALPS. 367 



That the amount of rainfall is greatest at the normal line of 

 cloud notation, iipproximately 3,000 to 4,000 feet in the Australian 

 Alps, will be seen by comparing the records from those stations, 

 such as Grant, 4,000 feet, in the Mitchell River, with those at 

 Dargo, 1,000 feet, in the same basin, only fourteen miles distant. 

 Thus, during three or four years the average rainfall at Grant is 

 probably tifty inches, at Dargo not more than thirty inches. 

 Independently of the elevation, the situation of the station largely 

 affects the precipitation of rain, which helps to increase the 

 difference. For instance — the trend of the Dargo River Valley 

 from Dargo is southerly, and although partly exposed to the 

 moisture-laden winds from the Pacific, it is nearly surrounded 

 by high ranges. Grant, on the contrary, is on the crest of a 

 high range fully exposed to the influence of south-westerly 

 moisture-laden winds which sweep up the Dargo and Wongun- 

 garra Rivers, and to the north-western winds, which are carried 

 across the Dargo High Plains from the valley of the Ovens and 

 its tributaries, 



The record from Mount St. Bernard, near Mount Hotham, 

 where I erected instruments some yeai^s since, also offers conclu- 

 sive evidence that the situation of the recording station is impor- 

 tant. Dr. von Lendenfeld in his interesting notes on the "Meteor- 

 ology of Mount Kosciusko," remarks— * "The amountof water preci- 

 pitated from mist without the formation of regular rain is much 

 greater than one generally assumes." This is no doubt true, but 

 it by no means follows that the total amount of water produced 

 on the summits of the Alps, is greater than at the levels I have 

 suggested. An instance shewing that the sub-alpine slopes on the 

 weather side of the ranges receives a greater actual supply 

 of rain than the summits of the mountain occurred during 

 our joint expedition to Mount Bogong, when we were camped 

 on the summit, the wind blowing from the north strongly, 

 while clouds were creeping slowly up from the south. On 

 top of the mountain there was at length a calm, and shortly 

 the rain commenced falling in the valley to the north, but 

 before the rain reached the summit of the mountain, the moisture- 

 laden clouds from the south forced up into a higher region of the 

 atmosphere would have precipitated the greater part of their 

 moisture on the northern slopes of the mountain, so that the 

 actual quantity of vapour converted into water would be less on 

 the summit than on the slopes. 



Snow falls at heights above 2,000 feet, but at the lower levels 

 seldom remains longer than a few days, tliawing quickly as it falls, 

 unless on the sliaded hill sides, where the frost hardens the crust. 

 The distribution of snow seems to be affected by many complex 

 causes ; it is noticed that at similar elevations, in the same 

 locality, the depth of snow after a fall is very unequal. It is 



* Proc. Linn. Soc. N. S. Wales, X. p. 40. 



