X 



Proceedings. 



Felruary 20th, 1855. 



Monthly Meeting. 



The President of the Society having been detained, Mr. Justice 

 Barry was invited to take the chair. 



The reading of the minutes of the last meeting was postponed 

 to the next meeting. 



The following Gentlemen were announced to have been admitted 

 members of the Society, since the last meeting : — 



The Honourable the Attorney-General, W. F. Stawell, Esq.; 

 Captain Pasley, RJE., Colonial Engineer; Wm. M'Crea, Esq,, 

 Colonial Surgeon; W. H. Archer, Esq., A. Registrar-General. 



The Honorary Secretary, informed the meeting that, in 

 compliance with the resolution of the last meeting, the com^ 

 mission appointed to investigate the statements set forth in a 

 paper read by Dr. Wilkie, on the Yan Yean Reservoir, went up to 

 that district and examined the reservoir, as well as the Plenty 

 River and its sources. They made measurements of the Plenty at 

 various parts, with the view, of ascertaining the average quantity 

 of water the river is capable of discharging. They likewise made 

 measurements of the main tributaries, viz., the western and eastern 

 arms, and traced the source of the latter to the top of Mount 

 Disappointment. The report of the commission, however,^ as it 

 involved a vast amount of calculation, as well as actual experiments 

 upon the evaporation, could not be laid before this meeting with all 

 the necessary details. He stated further that the commissioners 

 had furnished Dr. Wilkie with the result of their measurements^ 

 founded on which data his present paper was enlarged and amended^ 



Dr. Wilkie then read a paper on the Yan Yean Reservoir, founded 

 on the data above referred to. He endeavoured to show that there 

 would not be sufficient water in the reservoir, after deducting the 

 evaporation, to supply more than 75,000 individuals at forty gallons 

 per head per diem ; and he argued that on the constant-service 

 principle, the supply might be found altogether insufficient even 

 for that number ; he stated that it had been found by the ex- 

 perience of other cities that forty gallons could not be depended on 

 as a sufficient supply. He showed that from fifty to 100 gallons 

 per head per day were frequently used, and that several cities m 

 England have beenobhged to abandon the constant-service principle 

 altocrether from an insufficient supply of water. Dr. Wilkie also 

 strongly objected to the principle of storing water m a swamp, 

 and thought that it would become very much deteriorated and 

 incurably infected with animalculse and vegetable productions 

 which no filtration could remove. He entered at srreat length into 



