320 THE AQUARIUM 



Probably the most satisfactory is the glass aquarium with a 

 frame of metal. The cheaper grades have metal bottoms as 

 well, but the best and most serviceable are floored with 

 slate. Tanks of this sort are not at all difficult to make, 

 but the beginner might much better invest in the excellent 

 offerings of dealers in aquaria. There are many recipes for 

 aquarium cement, but their mixture is a matter calling for 

 some skill, and if the amateur pisciculturist essays the manu- 

 facture of a tank, or repairs are required, it is much better 

 to secure a packet of suitable cement already prepared. 



In. placing the aquarium, there are certain rules to be 

 observed. If they are to thrive, the plants must have a 

 varying amount of light, according to their habit, some 

 requiring more than others, but direct sunshine during the 

 summer months is most undesirable. In the first place, it 

 overheats the water, causing it to give off oxygen, thus often 

 imperiling the lives of the inmates. Most plants will not 

 do well under such conditions, and the growth of undesir- 

 able algae is certain to be caused. For these reasons, a 

 strong north light is the most suitable for the aquarium, 

 which should be placed in or very near a window. During 

 the winter a little sunshine during the morning is desirable, 

 and for this purpose an eastern exposure is best. Sunshine 

 at this time will serve to warm the water slightly, and will 

 stimulate the plants to a proper activity. If a southern 

 or western window is the only one available, the aquarium 

 may be protected to some extent by the introduction of an 

 opaque fender, such as a piece of cardboard, between it and 

 the light. A tank fully stocked is heavy, and its support 

 should be well looked to. 



A piece of glass should cover the top of the tank, under 

 any circumstances. If it fits tightly, leaving no air space 

 whatever, it will be found a world by itself, evaporating 

 water condensing on the glass top, and returning like natural 



