34 



THE FAMILY AQUARIUM. 



the garish sunlight, or to occupy in or der to escape ob- 

 servation. 



The water in the tank, it is hardly necessary to say, 

 because the intelligent reader will presume it to be ob- 

 vious, should be of good quality. For a fresh-water 

 Aquarium or River Garden, river, pump, or well water is, 

 of course, to be sought, and should be as pure as it may 

 be practicable to obtain it. Chalybeate water (water im- 

 pregnated with iron and certain salts), and spring waters 

 known to have mineral and other medicinal qualities, al- 

 though suitable enough for invalid humanity, are scarcely 

 suitable for an Aquarium. Nor will water that has been 

 boiled, to purify it, suit our purpose, for the process of 

 boiling expels too much of the oxygen, the presence of 

 which is absolutely necessary to sustain aquatic life. The 

 water we ordinarily drink, if well settled, is the kind to be, 

 in fact, selected ; and if it be poured back and forth from 

 one vessel into another, a few times, in order to aerate it 

 (impregnate it with air), nothing could be more apposite. 

 This aeration will be found a somewhat important consi- 

 deration in the maintenance of a thriving Aquarium. Its 

 effect is to impart, so to speak, fresh life to the water, and 

 restore the equilibrium which may have been seriously dis- 

 turbed by the want of an exact balance between your 

 combination of animal and of vegetable existence. At the 

 Dublin Zoological Gardens they have quite an ingenious 

 arrangement for aerating all the tanks of the Aquaria at 



