252 On the Management of Hothouse Flues. 



presently, the cover is drawn up from the top of the chimney 

 and the fire is lighted. The fire is continued burning till 

 eleven o'clock (three hours) when the flue and furnace are 

 closed again, till about four o'clock in the afternoon. They 

 are then re-opened, the fire kindled and kept in active com- 

 bustion till about eight o'clock. By this management the 

 fire is in action less than one-third of the twenty-four hours, 

 consequently two- thirds of the fuel, which would be necessarily 

 expended in keeping the fire burning the whole of that period, 

 are saved, as well as all night attendance rendered unnecessary. 



But there is another troublesome operation besides the 

 night attendance, which this plan, if it does not entirely pre- 

 vent, renders of much less frequent occurrence, and that is. 

 the cleaning of the flues. As two-thirds less fuel are consum- 

 ed, the soot produced is of course diminished, in the same 

 proportion. But it is not the soot only, or principally, that 

 choaks the flues, but the ashes which are carried into them by 

 the current of air, whenever the fire is stirred or the ash-hole 

 emptied. These ashes collect in heaps, the heaviest of them 

 just beyond the throat of the flue, and the lighter at the 

 different angles. To prevent which, whenever the fire is 

 stirred or the ash-hole cleaned out, the cap should be previ- 

 ously let down on the chimney top for the moment. This 

 instantly causes a recoil of the current of air, which blows out 

 of the mouth of the furnace those ashes which would other- 

 wise have been carried in, and have lodged in the flues. As 

 soon as the dust raised by stirring the fire, &c. has subsided, 

 the cap is to be drawn up again. 



By the aid of this simple apparatus thus regulated, I have 

 been enabled to keep up in my little stove through this win- 

 ter hitherto a higher, more equable, and regular temperature, 



