130 DESCRIPTION OF HOTHOUSES. 



with a sliding plate of iron, in a frame of irots 

 fixed in the brickwork near the fire-place, to- 

 slide across the flue, occasionally to reduce the 

 heat when it may be too "powerful, or to admit it 

 more strong when necessary. 



The fire-place or furnace from which the flues- 

 proceed, should be constructed outside the hot- 

 house at the back, the heat conveyed through a 

 single funnel, along next the end and front walls- 

 being continued to that behind. The fire-place 

 may be at one end or in the middle, and the 

 grate, formed of iron-work, should be about 

 fifteen or eighteen inches below the lowest flue, 

 which will give a proper draught for the smoke 

 and heat to ascend without returning ; also the 

 fire-place should be formed about twelve or four- 

 teen inches wide by about eighteen or twenty 

 deep, with an arched top, having an iron door 

 on hinges, placed at the mouth, to shut close, and 

 to be confined with a latch or catch. 



It is a desirable plan to have the fire-places 

 inclosed under a shed, for by being defended from 

 the weather both above and on the sides, is very 

 advantageous in preserving the regularity of the- 



