Modifying Climate. 127 



(2) Rainfall Increasing Eastwards without any 

 Apparent Cause. 



The whole rainfall distribution of the Riverina and Northern 

 Victoria suggests that the watering of large areas of country 

 -downstream from Echuca and Deniliquin has some influence in 

 •causing increased rainfall as we go eastward, since the rainfall 

 increases without any corresponding increase in altitude. It may 

 be as suggested by me in an article written in 1910, on the " Rain- 

 fall Distribution over Victoria," that these eastern areas derive 

 .some benefit from their being more in the way of " monsoonal " 

 disturbances than stations further west, but this should be bal- 

 anced to some extent by the greater accessibility of the western 

 stations to oceanic influences coming by way of the Bight. At 

 .all events the differences are most remarkable. To quote from 

 this article : " Benalla, with an altitude of 560 feet receives 26^ 

 inches, while Wedderburn, 8 feet higher, gets only 18 inches; 

 the altitudes of Balmattum and Sutherland are the same — 565 

 feet — yet the former receives 25 inches, and the latter only 15-J. 

 Wangaratta, 493 feet, receives 24.8 inches and Lubeck, 488 feet, 

 -only 17.4 inches, and so on. It may be remarked, too, that the 

 western stations are in somewhat higher latitudes, which should 

 help them. 



This phenomenon may perhaps be explained somewhat as fol- 

 lows : If we follow the 36th parallel from near the mouth of the 

 Murray inland, we notice a gradual decline of the rainfall which, 

 by the time we reach Tyrrell Creek, has dropped by more than 

 one-third, or from 21 inches to less than 13. This is evidently due, 

 at least in part, to the failure of local evaporating surfaces to 

 compensate for the rain since leaving the Bight. A change now, 

 however, begins to take place; atmospheric humidity must be 

 increasing, for without help from land altitudes the rainfall is 

 increasing, giving recovery at Echuca by 4 inches, and at Yarra- 

 wonga by 7 , or to that near the coast line. As the increase is 

 • coincident with entry upon country always undergoing natural, 

 and in recent years artificial, irrigation, it is reasonable to as- 

 sume some connection. The unimproved Mallee areas with their 

 uniformity of green drought-resistant scrub growth probably 

 evaporate evenly but miserly, and, as the country is flat, this 

 evaporation does not disturb the plane-like cloud formation 

 usual in front of oncoming storm systems, which may be one 



