162 OUR PUBLIC AQUARIA. 



aquaria at Brighton, Manchester, &c. A full and 

 detailed description of that at the Crystal Palace will 

 be found in the excellent ' Handbook ' which Mr. 

 Lloyd has written.* 



In large aquaria it would be utterly impossible 

 to sufficiently aerate the water in the huge tanks by 

 means of algae. The quantity required to be grown 

 to oxygenate the water sufficient for a very few fish 

 to be healthily kept would be so great that it would 

 almost fill the tanks. Moreover, in these show tanks 

 it is necessary there should be as little as possible to 

 obstruct the observation for which they are con- 

 structed. Even if sufficient aeration could be pro- 

 duced by the presence of sea-weeds, that alone would 

 not represent the actual marine conditions by which 

 fish and other animals are naturally surrounded. 

 The seething, restless condition of the ocean with its 

 huge volume of water moved by tides, currents, and 

 storms, so that the waves raised by the latter are 

 always entangling quantities of atmospheric air all 

 over its broad surface is best imitated in large 

 aquaria by the circulation which is constantly hurrying 

 masses of water from one place to another, and always 



* In 1 86 1 Barnum had two white whales captured for him at the 

 mouth of the St. Lawrence, and conveyed alive to his museum at New 

 York, where they were exhibited in large tanks constructed for the 

 purpose. Other tanks were shortly afterwards constructed by him, in 

 which sharks, porpoises, "angel" fish, &c., were shown. These 

 animals were kept alive by a stream of salt water from high tide. This 

 was the first rude attempt at aquaria in America. 



