inches in diameter and the same height. The best form of aquarium, however, is rectangular, with 

 soapstone or slate bottom, and with four glass sides or with ends of stone. The smallesl size to be 

 recommended is IS inches long, 9 or b> inches wide, and { > inches high. 1 1" room is available, the most 

 satisfactory size is 20, 24, or 30 inches long. The width should exceed the height, and for the largesl 

 size mentioned the width might be 12 to 14 inches and the height Ki to 12 inches. Cylindrical jars and 

 rectangular aquaria of all convenient sizes may be obtained from various dealers in all parts of the 

 country. 



The aquarium may rest on a window ledge, on a pedestal, on a stout table, or, if large, on a 

 specially constructed support. It should be placed where it will receive ample light, and the direct 

 rays ol the sun should enter the water for a part of each day, but should not be admitted in such 

 amount as to raise the temperature of the water unduly. 



The use ol running water in a house aquarium is usually unnecessar) and undesirable. By 

 observing conditions closely, it is possible to so adjust the various elements that an aquarium will 

 become "balanced," and will maintain itself indefinitely without change of water. This is importanl 

 and may be attained by adapting the number of fish to the volume of water, by securing a propei 

 oxygenizing oi (be water through surface absorption and plant action, by having plants take up the car- 

 bonic acid gas resulting from the vital activities of the fish, and by providing for the removal of waste 



products (excreta, unconsumed f 1. decaying vegetable matter, etc.) by the use of animal scavengers 



and by periodic cleansing on the part of the attendant. Under ordinary conditions, fresh water need be 

 supplied only to replace that lost by evaporation, the source of the water being immaterial provided it 

 is clear, ol proper temperature, not lacking in oxygen or containing injurious gases, and not strongly 

 mineral. 



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