THE PUBLIC AQUATIIUM 251 



bition tanks requiring nothing more complicated than mere connec- 

 tions with a city water system obviously can be operated at less ex- 

 pense than one requiring pumps for the circulation of sea water. It 

 would be possible for any inland city, not too remote from suitable 

 collecting waters, to maintain exhibits of fresh-water fishes and am- 

 phibians at small cost as compared with marine forms requiring stored 

 sea water. The flow of fresh water being automatic, the equipment for 

 operation can be reduced to very simi)le terms. With marine exhibits 

 the equipment and cost of maintenance would be altogether different. 

 The piping, if for permanent use with salt water, would be specially 

 constructed of vulcanized rubber, lead, or other nonrusting material, 

 with valves and other fittings to match. An underground reservoir 

 for the storage of sea water would be necessary, together with rust- 

 proof pumps of bronze for its circulation. Filters would be required 

 for the clearing of the water constantly flowing back to the reservoir. 

 With the use of pumps, which must run day and night, there would 

 follow an increase in the number of employees, some of them being 

 mechanicians requiring special compensation. If tropical forms of 

 life were added, water-heating equipment would be required to insure 

 their safety in winter. Cold water is necessary for northern forms of 

 life in summer. A large aquarium, in the latitude of New York, for 

 instance, requires a decidedly complicated equipment if its aquatic 

 exhibits include both northern and tropical fresh-water and marine 

 forms. 



The construction of a reservoir for pure sta water is imperative 

 even if the aquarium be located on the seashore. Experience has 

 shown that the water supply must be maintained in uniformly good 

 condition, unaffected by storms, changes in salinity, winter and sum- 

 mer temperatures, and the impurities of harbors. Unfavorable 

 variations in the water supply can not be avoided where water is 

 pumped directly from the sea. 



The prime requisite for keeping aquatic animals ift captivity is a 

 plentiful supply of their natural element, to which everything else 

 is subordinate. No completeness of mechanical equipment can make 

 up for deficiencies in this respect. The water supply must be pure 

 and abundant, whether for marine or fresh-water exhibits. 



The fresh- water supply of most cities is good enough for aquarium 

 purposes as it comes from the pipes, but during long-continued rains 

 or necessary alterations of the system by the city from time to time 

 the water may become murkey and remain so for weeks. Filters are 

 necessary, therefore, to insure the clearness of water desirable for 

 exhibition purposes. The filters receive the^water before it is deliv- 

 ered to exhibition tanks. In the case of permanently stored sea 

 water filters are also necessary, but they are so installed as to receive 

 the drainage of the exhibition tanks and return the water to the 

 reservoir clear and free from the impurities created by the feeding 

 of animals. 



Animal wastes in fish tanks are less injurious to the water supply 

 than bits of unconsumed food. All visible wastes should be siphoned 

 from the tanks before any disintegration takes place. Stored sea 

 water, like the freely flowing fresh water, must be kept in motion in 

 the exhibition tanks, which renders necessary the continuous 

 operation of pumps. 



