352 



THE AQUARIUM. 



cases, must be determined by local circmnstances ; but we should say one 

 of t^Yenty-^iye feet by twelve feet in breadth wotdd contain a very full 

 collection of these plants. The height in the middle should not exceed 

 eight feet, and the passage should occupy the centre, having a cistern of 

 slate, iron, or stone on each side, four and a half feet broad each, and two 

 feet deep, excepting at one end, where it should be two and a half or 

 three feet deep for the reception of some of the stronger growing kinds, 

 that require to. be grown in large pots or tubs, and whose foliage floats 

 on the surface. 



These cisterns should be fui*nished vdth. a waste pipe at one end for 

 the purpose of drawing off the water when necessary*, either entirely or 

 partially, to admit of a constant fresh supply, which is very necessary in 

 the cultivation of these plants ; and if this supply can be conveniently 

 brought by a pipe from some other cistern or source, it will render the 

 whole more complete. 



In regard to heating an Aquarium, hot water is certainly the best, and 

 for this pm'pose the pipes should be laid within the cistern, as shovm in 

 the sketch, by which means the water in it will be rendered tepid, and 

 give out its heat to the atmosphere of the house. The top pipe, however, 

 should not be more than half covered vdth water, which will allow a 

 considerable escape of heat from its upper surface into the house. In 

 the cistern through which the hot-water pipe runs, should be grown the 

 plants na.tives of the warmer parts of the tropics, and in the other, which 

 will be much cooler, the plants from more temperate chmates, thus, as it 

 were, combining a receptacle both for what are usually called stove and 



