THE BIRMINGHAM AQUAPJUM. 85 



THE BIEMINGHAM AQLMEIUM 



BY W. P. MARSHALL, ESQ., M.I.C.E. 



The first step towards the attainment of this desirable object (now 

 about to be realised) was the appointment of a Committee of the 

 Birmingham Natural History and Microscopical Society four years ago, 

 to obtain information on the subject, vdth the view of promoting an 

 efficient Marine Aquarium in Birmingham ; the subject ha^ving been 

 introduced by the President, Mr. W. E. Hughes, in an addi-ess at the 

 annual soiree of the Society. This Committee, after procuring inform- 

 ation fi'om different Aquaria in this country and on the continent, sent 

 a deputation to visit and examine the Crystal Palace Aquarium and the 

 Brighton Aquarium, for the purpose of obtaining practical information 

 about the requirements to be pi'ovided for, and specially to enquire into 

 the two different systems of circulation and aeration of the water that 

 are carried out at those places and the results of then* working. 



In the Crystal Palace Aquarium a constant circulation of the water 

 18 maintained night and day throughout the series of tanks, in connection 

 with a large reserve of water in the store tanks, amounting to five times 

 the contents of the show tanks ; and the aeration is effected by means 

 of small jets of water under considerable pressure, which are discharged 

 into the top of each tank, and carrj' down mixed with the water of the 

 jets a quantity of air, which is discharged in the form of countless 

 myriads of bubbles, so minute that they float a long time about the 

 body of the water in the tanks before rising to the surface, and thus 

 present an enormous oxidising surface to the water ; and, as a residt, 

 the whole mass has a bright, sparkling, almost effervescent appearance. 

 In the Brighton Aquarium the aeration is effected by pumping au- into 

 the tanks through pipes of considerable size, fx'om which the au* issues in 

 large bubbles that rise quickly to the surface ; thei'e is not any actual 

 circulation of the water from one tank to another, and the quantity of 

 water in the reserve tanks bears only a small proportion to that in the 

 show tanks ; the water can, however, be renewed, by pumping fi-om the 

 sea, but in consequence of the supply being taken from near the shore the 

 water is exposed to mixture with sand and other detritus, and requhes 

 some time to become clear. In the Crystal Palace Aquarium the original 

 supply of sea water for the tanks continues in use, and does not require 

 any renewal, except to replace unavoidable waste, all that is needed being 

 the addition fi-om time to time of a small quantity of fi-esh water to com- 

 pensate for the gradual loss that takes place from evaporation; the 

 supply of sea water in the store tanks — which are kept in the dark to 

 counteract the tendency to vegetable growth in the water — is so much 

 greater in quantity than the contents of the show tanks, that the 

 water after circulating through them becomes thoroughly restored to a 

 fresh and healthy condition before returning to the show tanks in the 

 course of the circulation. 



The result of the examination and enquiry of the Committee was 

 a recommendation of the Crystal Palace system, (which is the plan of 



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