134 HOT-HOUSE. 



Furnace and Flues. It is of great importance to havo 

 these erected in such a manner as will effectually heat the 

 house. The greatest difficulty is to have the furnace to draw 

 well. As workmen are not generally conversant on the sub- 

 ject, nor yet understand the effect or distribution of heat in 

 these departments, we will give minute details on their con- 

 struction. The furnace should be outside of the house, 

 either at the back or end ; the former is preferable, circum- 

 stances not always allowing it on the other plan. Dig out the 

 furnace-hole, or what is termed stock-hole, about five feet deep. 

 Lot the door of the furnace be in the back wall of the house, 

 thereby having all the heated building inside, that no heat 

 may be lost. The brick-work round the furnace should be 

 nine inches thick, laying the inside with fire-brick. Around 

 the outside leave a vacuum two or three inches wide, to allow 

 the heat to arise from around the furnace into the interior of 

 the house, thereby saving the whole heat of the fuel. The 

 furnace will require to be two and a half feet long, ten inches 

 wide, and one foot high, before the spring of the arch and 

 clear of the bars ; leave one foot for an ash-pit, then lay the 

 bars. They should be sixteen inches long, one inch broad 

 on the upper side, two inches deep, and two-eighths broad on 

 the lower side, and, with the door and frame, should be cast 

 iron. Half an inch between each bar will be sufficient. The 

 flue should rise from the furnace by a steep declivity of from 

 twenty inches to two feet, and pass the door of the house 

 (without a dip), when it must be elevated above the level of 

 the floor of the house along the front, and at the opposite 

 end of the house must dip to pass the door. The dip must 

 not be lower than the bottom of the flue at the neck of the 

 furnace. Lead it along the back to enter the wall over the 

 furnace. When thus taken round the house, the heat will 

 be expanded before it enters the chimney. The inside of 

 the flues should be from six to ten inches wide, and eight 

 inches deep ; plaster the bottom of it, but no other part, as 

 plaster is partially a non-conductor. The above description 

 is for burning anthracite coal ; but where wood is to be th^ 

 fuel, the furnace must be one-half larger. We have been 

 particular in the description of furnace bars, as those gene- 

 rally used are miserable substitutes. Circumstances may 

 cause the furnace to be placed at the end or front of the 

 house. In either case, the stock-hole will not require to be 



