262 



HEATING AS APPLIED IN HORTICULTURE. 



immediately in the front of it, so as to fill up 

 the space between the bars and the lower 

 part of the frame of the double door. 

 This fuel being dead between the bars 

 and the door, protects the door from the 

 heat of the fire, and prevents the iron 

 from warping. In supplying the fire 

 with fresh fuel, great care must be taken 

 not to throw it over to the farther end of 

 the fire, or into the throat of the flue, for 

 this is often the cause of flues bursting. 

 When coals are thrown beyond the fire, 

 after it has burnt low, and the flue is hot, 

 the heat of the brickwork generates gas 

 from the coals; this gas gets into the 

 flue ; and when the fuel over the fire be- 

 comes inflamed, if the flame be drawn 

 into the flue, it ignites the gas that has 

 been there generated, and causes an ex- 

 plosion. This ought to be particularly 

 attended to, as an explosion of gas in the 

 flue may destroy a valuable collection of 

 plants in a moment. 



"There is also another circumstance 

 which renders it desirable to attend to 

 the manner of supplying the fire with 

 fuel. If the fresh fuel be thrown over 

 the whole surface of the hot fire, it will 

 produce an immense volume of smoke 

 and black ; but, on the contrary, when 

 the fuel is added carefully to the front of 

 the fire, in the manner before described, 

 then much of the smoke given out by it 

 is consumed in passing over the hot part 

 of the fire. Besides the management of 

 the ash-pit register, the damper of the 

 flue ought particularly to be attended to, 

 by not opening it farther than is abso- 

 lutely necessary for the combustion of 

 the fuel. The more the damper can be 

 closed, provided the fire will burn mode- 

 rately well, the more will be retained in 

 the flue, without escaping up the chim- 

 ney, and the less will be consumed. And 

 when the fire is made up for the last 

 time in the evening, the damper should 

 be put in as far as it can be, so as only to 

 keep the fire just alive, and, in general, 

 the fire may be allowed to burn bright 

 against the last attendance in an evening ; 

 and then, instead of putting on fresh fuel, 

 close the ash-pit and damper completely. 

 This will prevent any draught of cold air 

 through the flues carrying the heat out 

 at the chimney ; and the body of heat 

 that is then in the mass of brickwork of 

 the flues, having no other means of escape 



than into the house, will frequently be 

 found sufficient for the night. 



"The ash-pit register should be pro- 

 perly attended to, and never suffered to 

 get injured with rust — not even in the 

 summer time, when not in use. The door 

 should then be taken off the hooks and 

 properly cleaned, and rubbed with oil to 

 prevent rust. The shovel used for the 

 fire-place should have a short handle, 

 which is as convenient for use as a long 

 one ; and, with a short-handled shovel> 

 the fuel cannot so easily be thrown over 

 the fire. The person who attends the 

 fires should be directed to use his hands 

 in opening and shutting the doors by 

 their proper handles, and not be suffered 

 to do it with a spade or shovel ; for, how- 

 ever strong they may be made, they may 

 soon be destroyed by improper usage. 



" It is of the greatest importance to 

 preserve the doors and ash-pits perfect, 

 for if they be injured, it is difficult to re- 

 pair them without taking them out of 

 the brickwork, which is attended with 

 considerable expense, and cannot be done 

 when the fire is in constant use." 



It would be superfluous to make any 

 comment on the merits of this excellent 

 paper. Many young gardeners, by read- 

 ing it carefully, will see how very few of 

 the conditions laid down are attended to 

 in everyday practice ; and although many 

 of them may console themselves with the 

 thought that they have not blown up a 

 hothouse flue, how many tons of coals, 

 and how many furnace doors, have they 

 wasted or burnt out ! 



In the construction of furnace stoke- 

 holes, it sometimes happens, in low situa- 

 tions, that drains cannot be got to the 

 bottom of the excavation. In such cases, 

 recourse must be had to caissons of iron- 

 work, or brick and cement, so constructed 

 that the water may be kept out of the 

 space where the furnace, &c, is to be set. 

 This is frequently done in Holland, when 

 dwelling-houses, which are often below 

 the levels of rivers and canals, are thus 

 secured against the inroads of water 

 from them. 



In regard to furnace-doors, we may 

 here observe that, of all others, Sylvester's 

 patent doors are the best for regulating 

 the draught in flues, as well as for lasting 

 long. They hang on a frame in which 

 they slide, the edges of the door and 



