The Scottish Naturalist. 353 



useful purpose of keeping a reserve stock for supplying the defi- 

 ciencies caused by the death of any of the animals in the tanks. 



It is contemplated also, if other Aquaria are established 

 in Scotland, and notably Glasgow, that the reserve stock might 

 be offered for sale. I am informed, on good authority, that the 

 Crystal Palace Company pay annually to the Brighton Aquarium 

 Company never less than ^"200. 



In the front centre of the building there will be a large en- 

 trance hall, measuring 45 by 28 feet ; and off this there will be 

 a small refreshment room, with lavatories, etc., etc., for ladies 

 and gentlemen, and for the use of which a small sum will be 

 charged. The large hall will be suitable for conversaziones 

 or concerts. 



The elevation to the sea has a frontage of 102 feet in length 

 and 22 feet in height, having a rusticated basement and cor- 

 nices, with an open balustrading above. In the centre of the 

 building a tower will project from the main line or front, rising 

 a few feet higher, and surmounted by a dome. 



There are thirty-six show-tanks altogether in the Aquarium 

 proper. These thirty-six tanks will contain 23,000 gallons of 

 sea water, and 9,000 gallons of fresh water. Besides this quan- 

 tity of water, it is essential for the more perfect aeration of the 

 water that the two reservoirs — which, I have already stated, are 

 to be placed underneath the building — must contain at least 

 four times as much water as that in the tanks : thus there will 

 be 92,000 gallons of sea water in the one reservoir, and 36,000 

 gallons of fresh water in the other. The depth of the water in 

 the reservoirs will be 5 feet, and thus a large surface of water 

 is kept in contact with the air to absorb oxygen. 



However to keep the watjer properly oxygenated, and cap- 

 able of sustaining animal-life, the water is kept circulating from 

 the reservoirs through the tanks, and back again by means of 

 water engines and pumps, the result of this continual motion of 

 the water being the absorption of a large quantity of atmospheric 

 air or oxygen. 



If the water were not thus kept in motion the oxygen would 

 soon be exhausted by the animals in the aquarium, the carbonic 

 acid evolved would soon accumulate, and the animals would die. 

 It is proposed to use a four-horse power turbine water- 

 engine (in duplicate) to circulate the water ; the turbine is so 

 constructed that the power can be varied as wished. To feed 

 the turbine 10,000 gallons of water will be required in the 



