140 Treubia Vol, III, 2. 



After having flowed through this large reservoir, the water discharges 

 from its Westerly end through duct C (Plan No. 4), into the Westerly end 

 of the second large Northern reservoir (4, Plan No. 4), 



Finally the water is pumped up at the East end of the last mentioned 

 reservoir, to be delivered to the tanks in the aquarium chamber. 



The dimensions of the large reservoirs are 12.70 M. by 4.70 M. by 

 1.30 M.; the capacity of each reservoir amounts, therefore, to 67V2 cubic 

 Metres; while the combined capacity of filter tanks, mixing reservoir and 

 large reservoirs totals 178 cubic Metres, 



As can be seen from Plan No. 4, there remains a T shaped accom- 

 modation way between the filter tanks and the reservoirs. 



Under normal conditions the cellar of the aquarium is in complete 

 darkness, but whenever it is necessary to work there it can be lit up by 

 electric light. 



Besides which wall plugs are fitted for connecting electric hand lamps, 

 by which means light can be played into all corners and holes. 



The extreme dampness in the cellar rendered it necessary to insulate 

 all lighting babies very carefully. 



Both in the North and South wall of the cellar are placed three light 

 proof ventilators, closed with mosquito-proof wire-gauze. 



Nevertheless, it appeared from a series of observations continued over 

 three weeks and taken with evaporimeters, that the evaporation in the 

 aquarium cellar while the reservoirs were .filled with fresh water, was 

 reduced to o. 



The accompanying Diagram, page 15, gives one a clear idea of the 

 sea water circulation in the aquarium. 



The numbers in the top half of the Diagram agree with those on 

 Plan No. 3, those in the lower half, however, agree with those on 

 Plan No. 4. 



The letters T' of the top half of the Diagram, are found back again, 

 without accent, on Plan No. 4; similarly with the top figures 4' and 5' of 

 the lower half of the Diagram, which are found back again on Plan No 3. 



Each of the three pumping sets referred to above, has its own suction 

 pipe of hard phosphor bronze, through which the water is pumped from 

 the Eastern end of the second, or Northerly, large reservoir — see D, Plan 

 No. 4, and D in the right hand lower corner of the Diagram '). 



Each of the three suction pipes is, necessarily, as far as a centrifugal 

 pump is concerned, fitted with a foot valve. 



') Only two instead of three suction pipes are shewn both on Plan No. 4, and in 

 the right-hand lower corner of the Diagram at D. 



Also in the left-hand top corner of the Diagram at D, three suction pipes are 

 shewn intead of one. 



Both of these errors are due to the fact that the suction and delivery pipes of 

 hard phosphor bronze finally installed, differ a little from the suction and delivery 

 pipes of earthenware which were originally proposed. 



