282 THE FORCING GARDEN. 



The sole of two inch thick tiles, each fifteen 

 inches long, by twelve broad ; jointed on cross 

 bricks on edge, or pillarets, to keep them about 

 four inches clear of the surface. The walls of 

 well moulded, or stock bricks, six inches clear of 

 each other, and the height of two bricks placed on 

 edge, covered with inch and half thick tiles, each 

 twelve inches long and ten broad, laid the length to 

 the run of the flue ; by which means the covers will 

 not be flush with the sides of the flue, but each edge 

 will be champhered or bevelled, which makes the 

 flue look very light and neat. The open or void of 

 the flue will thus be (with the height of two bricks 

 on edge, and two joints of lime), ten by six inches, 

 or thereby. It is clear and detached on all the four 

 sides, except the interruptions of the pillarets 5 and 

 is the most effectual flue of many different sizes I 

 have tried, as said above. 



The joints should be carefully filled with fine 

 lime, in soles, walls and covers ; but no plaster 

 should be used, either within or without. It is a 

 gross error to plaster any flue ; as by doing so, the 

 heat is conducted out at the chimney, instead of 

 being let into the house through the pores of the 

 bricks. A few feet, that is, six or eight, next to 

 the furnace, should be of fire-bricks and tiles, in 

 order to withstand the strong heat ; and the flue 

 should always extend quite through, to the outside 

 of the wall of the hot-house. The furnace, whe- 

 ther placed at back, front, or end, should never 

 come within the house. This is a measure of pre 

 cautiQii very necessary to be taken ; as many acci* 



