HEATING BY FLUES. 



151 



Fig. 158. 



Fig. 159. 



saved, and the second greatly remedied, 

 as a useful labourer can do the whole, 

 and this at times when the houses are not 

 likely to be visited by their owners. The 

 value of the soot, as a manure, is equal to 

 the expense of cleaning them, and the 

 saving of fuel will be considerable. 



Regarding flues, we hold that they 

 should be built much larger than they 

 in general are, for reasons elsewhere 

 given, particularly those by Mr 

 Lyle of Newburgh ; and, as an 

 improvement even on these, 

 we would suggest the introduc- 

 tion of fire-clay tubes placed 

 either vertically, fig. 158, or 

 horizontally through them, 

 fig. 159, and about 18 inches asunder at 

 the end farthest from the furnace, and 

 say 3 or 4 feet apart nearest 

 the fire. The ends of these 

 tubes being open in whichever 

 position they are placed, a cir- 

 culation of air would necessarily 

 pass through them in conse- 

 quence of their being exposed to 

 the internal heat of the flue. Thus they 

 would operate in the same way as the 

 hot-water pipes alluded to in section Va- 

 rious Modes of Heating. 



And where the flue passes along near 

 the front of the house, 

 which is the most usual 

 position for them, tubes 

 may be made to pass 

 through the parapet 

 wall, fig. 160, — thus ad- 

 mitting air from with- 

 out, which, being heat- 

 ed in passing through 

 the flue, will be found 

 exceedingly beneficial to 

 the healthy state of the atmosphere 

 within. 



In the case of a hothouse projecting 

 in front of the rest of the range, or in case 

 of a house stand- 



Fig. 160. 



Fig. 161. 



wsMm^ .Jim 



ing by itself, the 

 flues may be 

 readily cleaned 

 by having an 

 opening 9 inches 

 square through 

 the end, and also 

 the front para- 

 pet, as at a a, 

 fig. 161, to be 



secured by a cast-iron door set in a 

 frame, both at the inside, and one also 

 at the outside of the wall, and com- 

 municating with the flue. These, when 

 opened, will admit of a brush fixed 

 to a handle, to which additional lengths 

 can be screwed on, to brush down 

 the soot as far as the middle of the 

 house. The brush being withdrawn, 

 a hoe to draw out the soot, the exact 

 width of the flue, is then to be intro- 

 duced, and the handle lengthened by 

 screwing on the detached lengths of the 

 brush handle. The same operation, per- 

 formed at the other end of the flue, will 

 clear it from end to end. The end flues 

 may be cleaned out in the same way, as 

 will appear sufficiently obvious from our 

 diagram. By this means the usual filth 

 and confusion which attend the opening 

 of the flues within the house will be 

 completely obviated. If the parapets are 

 built of stone, as is frequently the case, 

 particularly in Scotland, a 9-inch block 

 of stone, with a folding-down ring in its 

 face, may be substituted for the iron 

 doors. In this case, however, it would 

 be as well that the stone be in length 

 equal to the thickness of the parapet, 

 and that the flue at these parts be also 

 built into the parapet, to prevent the 

 smoke from escaping by the space 

 between the parapet and the flue. 



A precaution against the bursting of 

 flues, from the explosions which may arise 

 by the ignition of inflammable gases, has 

 been exemplified for years in the gardens 

 at Pitmaston, near Worcester. It consists 

 of a hinged iron safety-valve, framed in 

 iron, and set in the brick-work at the 

 end of the flue. It is 8 inches by 6, 

 and opens into the external air. It is 

 kept closed by its own weight; but inter- 

 nal pressure, resulting from the explosion 

 of inflammable gases in the flue, would 

 throw it open and allow of their escape. 



Notwithstanding all that has been 

 written and experimentally proved re- 

 garding the great waste of heat, even 

 when the very best kind of boiler or 

 furnace is used, by its escape into the 

 chimney, still we see few attempts made 

 in practice to remedy this, or to turn 

 that heat to advantage. That a portion 

 of heat will thus pass by the boiler or 

 over the furnace is quite certain, and to 

 arrest it all would be impossible; to 



