Mr George Brook on the Aeration of Marine Aquaria. 383 



Pumping Arrangements and Motive Power. 



After careful consideration I ^Yas led to adopt water from 

 the town mains as a motive power. It seemed advisable to 

 make use of some powder wliich could be cut off or started at 

 will by some automatic arrangement, and Avater on this 

 account seemed the most applicable. I decided from the 

 outset not to supply tlie salt water direct from the pump to 

 the jets, as is done in so many large aquaria, but to pump it 

 into a store tank at a considerable elevation above the floor 

 of the building, and use the fall thus obtained to force the 

 water into the tanks. Further experience has shown that 

 this is in the long run the more economical plan, and without 

 this elevated tank I could not obtain the satisfactory results 

 already arrived at. I began, then, with one of Eamsbottoin's 

 Water Motors, and a rotary vulcanite pump, supplied by a 

 1-inch pipe from the reservoir. It then became necessary to 

 devise some automatic stop motion for the water motor, so 

 that the whole arrangement could be stopped when the fall- 

 tank was full, and started again when the water had run 

 down to a certain level. A continuous circulation could 

 then be kept up day and night without any w^aste, and with 

 little or no attention. 



Several modifications of the principle of the ball tap were 

 tried wdth varying degrees of success, until at last one was 

 arranged which acts perfectly, and is showm in Fig. 1. A is 

 a wood float connected by an adjustable arm B w4th the 

 lever C, which is supported on the edge of the tank by the 

 pillar D. In use it was found that the float A, on beino- 

 forced up by the water, was liable to leave the side of the 

 tank, so that a double-jointed arm I, I', had to be fixed on 

 the opposite side to keep it in its place. E represents the 

 arm which goes down to the tap, and F is a w^eight corre- 

 sponding to that of the long rod E, so as to balance the 

 arrangement. As the float A is forced up, of course E is 

 low^ered to a corresponding degree, and would be gradually 

 shutting off the tap of the motor, unless steps were taken to 

 prevent this being done until the fall-tank w^as full. It will 

 be observed, however, that the arm B is slotted at its upper 



