MANAGEMENT OP THE AQUARIITM. 51 



in the bottom of the aquarium in the same way as B has 

 been; its length -within the tank will of course regulate the 



Fig. 39. Aquarium containing an Basily-arranqed Fountain. 



height of the water there. If the aquarium is made of slate, 

 there may be an overflow-pipe at G (instead of F), fixed in 



E 2 



