POLMAISE MODE OF HEATING GREEN-HOUSES. 



127 



means, and the tile or split brick must not 

 touch the edge of the plate, but i an inch 

 space is to be left between the edge of the 

 plate and the edge of the tile. The four 

 pieces of plate iron are then to be laid upon 

 the tile round the stove, and a course of 

 brick work upon these again, to keep them 

 steady ; and they are to be so placed that 

 they project over the four edges of the 

 plate till within i an inch of the rib of iron ; 

 they will thus cover over an ^ inch clear 

 space all round the edge of the plate 

 (marked I ;) into this the plate can freely 

 expand, while upon these thin pieces of 

 iron, between the top brick and the rib on 

 the plate, fine sand is laid, the position of 

 which can never be deranged b}"^ the ex- 

 pansion of the plate, as is the case if the 

 sand were laid in the space I ; while, if the 

 plate is cast with a rim falling into a groove 

 of sand, the sand prevents its expansion, 

 and it either cracks or arches, and in time 

 is lifted out of the groove, the sand getting 

 underneath it. 



I. The i inch space above explained. 



K. The flue, formed of cast iron (hot 

 water) pipe, a socket, an elbow and straight 

 piece rammed together with iron filings 

 and sal ammoniac ; this conducts the smoke 

 into the old flue in stoke-hole, pipe 4 inch 

 bore ; it is swept out by a flexible brush at 

 the soot door, K, and being swept by the 

 blast it forms a considerable addition to the 

 heating power ; the socket fixes into the 

 brick of stove exactly like the door, having 

 a piece of plate iron screwed on to its inner 

 rim like the doors, and for the same purpose. 



L. Cast iron water tank with division, 

 one or both sides being kept full, according 

 as much or little atmospheric moisture is 

 required ; the purposes to which the house 

 is devoted must regulate the size of this ; 

 if for a moist stove temperature it cannot be 

 well too large, if for green-house, 2 feet by 

 3 feet will be ample with division ; the bot- 

 tom of the tank also forces the air over the 

 plate before allowing it to escape. 



M. Flange on doors, already explained. 



N. The flap of door which hangs on a 

 pivot, lifting on or off"; the ash-pit door is 

 represented with flap open, the opening is 

 enlarged or decreased as m ich or little air 

 is required for draft to the fire. 



O, Fire bars 3 inches thick, forming a 

 square of 18 inches ; care must be taken 

 that these do not bind in the brick work of 

 the stove ; they should have half an inch 

 play allowed. 



P. Is a screen of slate with some holes 

 in it (as shown in ground plan) for the pur- 

 pose of forcing the greater part of the cold 

 air to pass under the stove and up the three 

 other sides, instead of allowing it at once to 

 pass up the sides nearest to it, while the 

 apertures allow a portion to pass up. 



R. Soot door in flue. It would be well 

 to have a damper just beyond this. 



S. A screen for the purpose of forcing 

 the hot air over the tank before it dis- 

 charges itself into the house, and also 

 to prevent the intense radiation of the 

 stove. 



T. The hot-air chamber, 5 feet 2 inches 

 deep, 4 feet wide, (inside measure;) the 

 walls are formed of brick on edge. If the 

 ground is loose this should be 4^ inch brick 

 work ; excavate sufficient to allow 2 or 3 

 inches of saw dust to be thrown down be- 

 hind the wall of the chamber. 

 Remarks. 



It is not necessary that the entire appa- 

 ratus be thus sunk below the level of the 

 green-house, although it is desirable to 

 give the cold air drain as much fall as the 

 nature of the ground will allow — it is quite 

 immaterial what position the cold air drain 

 or the stove occupy; they may each be 

 placed where most convenient. The circu- 

 lation of air caused by the apparatus of 

 which this is a description is very great, so 

 much so, that when the entire house js 

 closed, the internal motion may be fairly 

 described as a breeze; while the economy 

 with regard to fuel will be found extremely 

 great; the positive consumption will be 

 best stated in the coming winter. The 

 stove is 9-inch work ; any person at all 

 fearful of gaseous leakage may at once ren- 

 der this impracticable by using l4-inch work 

 with a layer of sand even half an inch thick 

 between the 9 and outer 41; or this provision 

 may be made for safety-sake on the side 

 where the cast iron flue leaves the furnace; 

 such a stove would for :i an immense ac- 

 cession of heat, though the temperature 

 would be long rising. 



