SPECIAL NUMBER ON SMALL AQUARIA 

 By Raymond C. Osburn 



ZOOLOGICAL 

 SOCIETY BULLETIN 



Number 50 Published by the Xcjc York Zoological Societi/. March. 1912 



THE BALANCED AQUARIUM. 



THE small aquarium as an object of interest 

 and decoration in the house has become so 

 common that its presence no longer attracts 

 special comment. The custom of keeping such 

 aquaria is, however, of comparatively recent 

 origin. Goldfishes have been kept and bred by 

 the Chinese and other oriental peoples for sev- 

 eral centuries, though, to be sure, this was most- 

 h' done in small out-door pools in the gardens. 



The balanced aquarium has been clearly de- 

 fined by 'Sir. Henry D. Butler, in a book en- 



titled The Family Aquarium (New York, 1858), 

 in the following terms: "The aquarium is a re- 

 ceptacle for aquatic animal and vegetable life 

 in fresh or salt water, which need never be 

 changed. The old-fashioned fish globes were 

 not acjuaria in the proper sense, because it was 

 absolutely necessary to change the water in them 

 pretty frequently, lest the fish die. The vital- 

 ization of the water without this change com- 

 preliends the leading principle of the aquarium." 

 Undoubtedly the failure to grasp the principle 



FRESH AND SALT-WATER BALANCED AQUARIA IN THE NEW YORK AQUARIUM. 



are near the windows, the fresh-water ones beneath skylights. These aquaria have bt 



observation by public school teachers and their classes. 



