166 OUR PUBLIC AQUARIA. 



adjacency of the aquarium to the sea somewhat 

 obviates the necessity for a large storage reservoir. 

 The sea itself may be regarded as partly acting in 

 that capacity, for all the salt water in the tanks is 

 pumped directly from it into underground reservoirs, 

 capable of holding half a million gallons of water. It 

 takes about ten hours to fill these reservoirs. The 

 circulation of the sea water in the tanks is carried out 

 by means of compressed air, which is supplied to 

 their lower parts. One supposed advantage in this 

 method of directly injecting air into the bottom of 

 each tank is that it will ascend through the entire 

 volume of water, and will, moreover, first come into 

 contact with any organic substances lying at the 

 bottom, which require oxydisation. Another assigned 

 reason for employing this system of aeration and 

 circulation is its greater cheapness. This, however, 

 Mr. Lloyd emphatically denies ; even holding that it 

 is eventually more expensive. We may expect, how- 

 ever, that many of the public aquaria founded at 

 seaside towns and resorts will be established on the 

 Brighton pattern, owing to the advantages which 

 contiguity to the sea confers, by enabling the manager 

 to pump in the sea water direct, and as often as may 

 be required. It has been found that the salt water 

 near the shore is quite fit for aquarium use, especially 

 if it be kept a time in the reservoirs, so that any 

 mechanical sediments, &c., may subside. Another 

 assumed advantage of the Brighton system of direct 



