O. 12.] EXPLANATION OF THE PLATES. 2J3 



of it, and bring forward two or three 

 fliovel-fulls of fire to the front ; behind 

 which, throw the quantity of frefli fuel 

 required, (hut the door clofe, and in the 

 fpace of an hour or fo, revifit it to fee how 

 the fire is burning. If it is burning too 

 flow, ftir it up by applying the fire-poker 

 (the end of which is turned up) under- 

 neath the grate, clearing the interfaces 

 of the bars the whole length ; but if it is 

 burning too rapidly, open the furnace- 



)or a little way ; by which means the cur- 

 rent of air will be divided, part of it paffing 

 over, and part of it through the fuel. In 

 the fpace of another hour, again pay it a 

 vifit ; (having previoufly confulted the 

 thermometer in the hot-houfe) ; and if 

 the fire is> confuming too faft, open the 

 furnace-door accordingly } but if too flow, 

 * fliut it clofe altogether. 



This method is much preferable to that 

 of working by dampers, it being very dif- 

 ficult to hit on the exact proportion of 

 the aperture to be left in the vent ; be- 

 fides, whatever air pafles through the vent 

 muft alfo pafs through the fuel, and that 

 too with greater velocity than when the 



damper 



