32 



THE FAMILY AQUARIUM. 



to the floor of the tank, as though they were a luxuriant 

 growth of arborescent madrepores. The rock work in the 

 centre may be of any kind of stone whatever. Two points 

 in this connection, must be peremptorily attended to, 

 if you desire to see your Aquarium meet your sanguine 

 expectations ; the one is the production of your rockwork 

 across the tank, with a careful eye to the elevation of the 

 same point of it above the surface of the water ; the other 

 is the soaking of the tank itself for a considerable period 

 after the use of the cement. The purpose of the elevated 

 rock v/e have already alluded to, in speaking of such ma- 

 rine animals as require an occasional exodus from the world 

 of waters. The object of well soaking the tank is to remove 

 the free lime that may be disengaged from the cement, as 

 its subsequent incorporation with the water of the Aqua- 

 rium would be destructive to all of the animal life it might 

 contain. The only safe mode of ascertaining when this per- 

 nicious transfusion has completely ceased, will be to con- 

 tinue soaking the tank, by filling it with clean water and 

 removing the latter as fast as it becomes impure until the 

 prismatic scum, which you will have noticed on the sur- 

 face, entirely disappears. When you are quite confident 

 that it has ceased to present itself, and neither your sight 

 nor your scent can, with the keenest effort, detect the 

 presence of the slightest soil or effluvia, your tank will be 

 ready for use. 



You may now prepare the bed of your Aquarium with the 

 certainty of having proceeded with a caution worthy of 



