Van Yean Reservoir. 



185 



I have arrived, therefore, at the conclusion, that in ordinary- 

 years no fear need be entertained, but that a very abundant 

 supply of water will be derivable from Yan Yean, for a 

 population three times greater than the present population 

 of Melbourne. But that, whenever this colony is again 

 afflicted with such another drought as that of 1838 and 1839, 

 a failure in the supply would occur. 



The great area of the reservoir will cause the water to be 

 occasionally so violently agitated by wind as to obviate some 

 of the evils that arise from the storage of water. I do not, 

 therefore, anticipate that the Plenty water will undergo 

 much deterioration in the reservoir, unless during the preva- 

 lence of an extraordinary drought. 



It has been suggested, that if an additional supply of 

 water be required, it could be conveyed into the i-eservoir 

 either from the King Parrot Creek, on the other side of the 

 main dividing range, or from the Diamond Creek. 



I believe the able engineer of the Water Commission 

 could not have examined these streams closely. For I have 

 inspected the source of the King Parrot Creek, and being 

 also acquainted with the country within the watershed of 

 the Diamond Creek, I am induced, from my local knowledge, 

 to form a very unfavourable opinion of this mode of increas- 

 ing the supply. 



In the case of the King Parrot Creek, a drift-way of 

 considerable length would have to be made, at a great depth 

 below the surface, through hard, igneous or plutonic rock, 

 and the difficulties attending the execution of such an exces- 

 sively costly work, would probably be augmented by the 

 influx of water during its progress. With regard to the 

 Diamond Creek, several of its tributaries, and steep interven- 

 ing schistoze ranges, would have to be crossed, before the 

 waters of the main creek could be conveyed to the Yan Yean 

 Reservoir, In point of fact, the western tributary of the 



tine bands of mist defining the courses of rivers or large sheets of water; and 

 in Australia I have occasionally, on clear nights, seen similar mists suspended 

 over lagoons, and which mists saturated my hair with moisture on traversing 

 them . Mists of this very circumscribed nature are much less frequent in Aus- 

 tralia than in Europe ; yet, if they resulted, as some have supposed, from the 

 temperature of the air being below that of the surface of the water, such mists 

 ought to be of more frequent occurrence here, where the temperature of the 

 atmosphere during night is so remarkably less tha,n during day, and conse- 

 quently the temperature of water surfaces during night generally greater than 

 that of the air. I venture to hope that the phenomena connected with vapour 

 in the atmosphere here will be elucidated by Mr. R. Brough Smyth, whose 

 accurate and judiciously conducted observations will ultimately render his name 

 our chief authority on the Meteorology of this Colony, 

 X 



