182 



Transactions. — Miscellaneous. 



of tlie lake during the 17tli and ISth November. This quantity is equivalent 

 to a depth of 1'439 inches per diem run off the whole drainage area. 



The observed rainfall at Queenstown during the two days being 2-27 

 inches or 1'135 per diem, of which we can only count upon three-fourths 

 as having run off (this being the proportion observed to do so in similar 

 districts in Europe) we can only attribute -851 inch over the whole area to 

 rainfall. Consequently the difference must be derived from the melted snow 

 and ice running from the mountains. 



I may observe here, that Queenstown being nearly at the centre of the 

 drainage area, the registered rainfall may be taken as a fair average ; and 

 that at the late period of the season when this flood occurred, the snow 

 on the mountains immediately surrounding the lake had almost entirely 

 disappeared. 



The following table will give the above results more clearly : — 





Cubic feet 



per minute jjer 



square mile. 



Cubic feet 

 X)er minute. 



Equivalent depth 



run off per diem. 



Indies. 



Rainfall 

 Snow . . 



1,373 

 950 



1,647,600 

 1,140,000 



•851 

 •588 



Total . . 



2,323 



2,787,600 



1-439 



From the above figures we can approximate the proportion of the flood- 

 water running into the head of the lake by the rivers Dart and Eees : — 



Rainfall . . 

 Snow 



Sq. Miles. 

 1,373 X 400 = 549,000 

 950 X 1,200 = 1,140,000 



Total Cubic Feet pee Minute . . . . 1,689,000 



As in the former table it was shown that the total flood-water amounted 

 to 2,787,600 cubic feet per minute, it is evident that considerably more 

 than half the whole quantity rushed into the lake at the extreme north 

 end, or head as it is termed. Accepting these to be the facts, the question 

 is, — Would this mass of water flowing rapidly (possibly in much less than 

 forty-eight hours) into one extremity have sufficient effect to cause the 

 disturbance observed ? 



I have been unable to find any other explanation, and believe that the 

 following are the reasons. I would ask you to examine the conformation of 

 the lake, and observe that it is throughout a long and narrow one, and that 

 opposite Queenstown there are two bends or elboAvs of more than right 

 angles ; in point of fact, a wave passing down the lake would be deflected 



