9<32 THE BOOK OF GARDENING. 



Heating.— For heating a tank of the dimensions given, two 

 4in. pipes (a flow and return) carried round the inside, about 6in. 

 from the walls and the same distance from the bottom, will be 

 quite sufficient, and these should be furnished with valves on the 

 outside of the tank . to allow of regulating the temperature of 

 the water. An air-pipe should be fitted to the flow-pipe at its 

 highest point, to release any air or steam that may accumulate 

 in the pipes. The tank should be furnished with a plentiful 

 supply of water, and a tap connected with the service-pipe, so 

 that it can be turned on to its full capacity when the tank 

 required refilling, or regulated to a gentle flow when the Aquatics 

 are in full growth, or as desired. An overflow stand-pipe is 

 also necessary, the top of which should reach to nearly the full 

 height of the tank. If constructed in two parts somewhat on 

 the telescope principle, so that the upper portion may be raised 

 or lowered by sliding or screwing into the bottom part, means 

 will thus be afforded for keeping the water at any desired height. 

 A large brass perforated cap similar to the rose of a watering- 

 can should be fitted to the top of the overflow-pipe to prevent 

 floating matter from choking it, and the escape of small Aquatics. 

 This stand-pipe . should be situated conveniently close to 

 the wall. It should, be fitted into another pipe, set level 

 with the bottom of the tank and connected with the drain pro- 

 vided, so that when any operations necessitate the tank being 

 emptied the stand-pipe could be removed and the water readily 

 drained off. 



If it should b e considered desirable to paint any part of the 

 tank that is above the ground-level, it will be best to defer doing 

 so for a time, as the new cement would blister the paint and 

 cause it to peel off. 



It is not advisable to plant a new tank immediately after it 

 is finished, but it may be filled with water, which should be 

 allowed to stand for at least a week. The scum that will 

 have by this time accumulated on the surface should be 

 flushed and syringed off, and the tank then filled up with fresh 

 water. 



Arrangement of Tubs, Pots, etc. — The next important 

 operations are the arrangement of the tubs or large pots in 

 the tank, and preparing the soil in which the Aquatics are to 

 be planted. Of course brick enclosed beds may be more 

 freely introduced where plenty of room is afforded for growing 

 very large specimens ; but in a tank of limited dimensions where 

 it is desired to grow several plants of moderate size, tubs or 

 large pots will be the most suitable, as these have the advantage 

 of being readily moved. If tubs are employed — and perhaps they 

 are preferable for an indoor tank — a very useful size will be 

 found in those measuring about i8in. square, and the same in 

 depth, with the angles securely dovetailed. They are best made 



