PITS HEATED BY HOT WATER, &o. 



439 



the circulation of the water by stopcocks 

 near the boiler. The water in the tanks 

 will cool down, and give off little vapour ; 

 while, the flue heat being increased, a 

 sufficient supply of dry air will ascend 

 into the pit. An opening, with a door, 

 should be placed at one end of this pit, 

 to admit a man entering to clean the 

 flue, as all flues extending to a great 

 length in a horizontal position very soon 

 become choked with soot, unless coke or 

 very superior coals be used. The flue is 

 not intended to heat the tank, but to 

 throw dry warm air into the atmosphere 

 of the structure above. 



Fig. 608 is the section of a plant pit, 



which may 

 m ' ^z^i also be used 

 for many 

 other pur- 

 poses. It 

 is 18 inches 

 under the 

 ground - le- 

 vel, and 

 filled with suitable material to the desired 

 level, on which the pots are to be set. 

 It is heated by hot water, the pipes being 

 supported on 4|-inch brick piers. The 

 roof is at an angle of 18° to the horizon. 



Niveris pine pit, fig. 609. — These pits 

 are substantially built, and well adapted 

 Fig. 609. 



heat is supplied by the same means through 

 the tubes or open pilasters ; and that 

 humidity may be commanded by admit- 

 ting water into the tank to be heated by 

 the under course of pipe to cause evapo- 

 ration, to modify the heat of the pipes in 

 the vault, as well as to find its way into 

 the atmosphere of the pit through the 

 tubes or hollow pilasters. The vault is 

 covered with pavement, upon which is 

 placed the necessary drainage of broken 

 brickbats to the thickness of 6 or 8 

 inches. Thin turf is laid on the drainage, 

 and on that the bed is formed for the 

 reception of the plants. 



Glendinning's melon pit, fig. 610. — The 

 Fig. 610. 



for general purposes, as well as for that 

 of growing pines. The figure will fully 

 explain their principle without any length- 

 ened description : a a are hot-air tubes, 

 or open pilasters, which can be opened or 

 shut at pleasure ; b is the bed of compost, 

 &c. ; c c are hot-water pipes ; d is the 

 hot-air chamber ; e the steps and platform ; 

 / the line of water; and g the ground line. 



It will be seen that bottom heat is 

 supplied by means of hot-water pipes in 

 the vault below the bed, and that surface 



annexed section and description will ex- 

 plain the merits of this pit, the invention 

 of Mr Glendinning of the Chiswick nur- 

 sery, one of the most intelligent horticul- 

 turists of the present day. " It is heated 

 by Burbidge and Healy's boiler, d d, in 

 section, iron troughs ; e e hot- water pipes ; 

 / / copper tubes fastened to the troughs 

 to admit steam when required; g wire 

 trellis on which to train the plants ; h a 

 convenient place for the growth of sea- 

 kale, rhubarb, or asparagus, or keeping 

 tubers of any kind during winter ; i cis- 

 tern." — Gard. Chron. 



This pit may be used either for the 

 growth of melons, or, without any mate- 

 rial alteration, for young pines, as the 

 hot-water apparatus is so arranged 

 that bottom and surface heat may be 

 had together or separately, as required. 

 A layer of flints or broken stones is 

 placed over the bottom of the bed, to 

 prevent the roots of the plants from com- 

 ing in contact with the iron troughs ; and 

 on this the soil is laid. A cistern is 

 placed at one end, into which the rain 

 water from the roof is received, so as to be 

 at all times in a fit state for the plants. 



