52 



occupants, and in his drawing too, if he can take the drawings 

 given here and try his hand at a difficult subject Hke this for 

 school use. 



After the box is made it would be well to let it stand in water for a 

 day or two. The wooden sides will swell and tighten the joints, and 

 leaking will be less probable. 



It is now time to begin to think about what sihall be kept in the 

 aquarium. At the bottom a layer of sand, the cleaner the better, 

 two or three inches deep will be needed. A few stones, not too 

 large, may be dropped in on top of this first layer, to make it more 



natural. 



The water plants come next and will thrive 

 best if planted securely in the sand. The most 

 diffiult thing is to get the water in without 

 stirring things up. A good way is to pour the 

 water in a slow stream against the inside of the 

 aquarium. The best way is to use a rubber 

 tube siphon, but even then the water ought not 

 to flow from a very great height. If the 

 aquarium is large it had better be put in its 

 permanent place before filling. 



The aquarium will soon be ready for snails, 

 polliwogs, and whatever else we may wish to 

 put into it. In the course of a few days the 

 plants will be giving up oxygen and asking for 

 carbon dioxide. 



Plants which thrive and are useful in 

 aquaria. — Many of the common marsh or pond 

 plants are suitable. The accompanying illustrations show a few of 

 these. Nothing can be prettier than some of these soft, dehcate 

 plants in the water. The eel-grass, or tape- grass (figure 6), is an 

 interesting study in itself, especially at blossoming time when the spiral 

 stems bearing flowers, appear. 



Any who are especially interested in the life-history of this plant 

 can read in reference books a great deal about what other observers 

 have learned from the plant about its methods of growth and 

 development. The best that we learn will be what the plant itself 

 tells us day by day. 



Fig. 6. — Eel-grass. 



