REMARKS ON THE ARNOTT STOVE. H 



through a, valve in the ash-pit door, an objection arose, that the con- 

 tinued extraction of atmospheric air, for several hours, from a closed 

 house, would probably injure the health of the plants ; to obviate 

 which, I admit the air from the potting-room, through the wall to 

 which the stove is attached, by a copper pipe two inches in diameter 

 conveyed horizontally to the ash-pit; and at the exterior end thereof 

 is a regulating valve, with balance weight to adjust at pleasure, made 

 on the principle of the plug valve recommended by Dr. Arnott, and 

 similar to that applied to one of the fancy stoves. I find this valve 

 answer my purpose well, as I regulate it the last thing at night 

 according to the appearance of the weather and the state of the 

 thermometer; but the very best valve for an Arnott stove is the self- 

 adjusting one, brought into action by the expansion and contraction 

 of a bar of metal placed within the stove, as it is unerring and not so 

 liable to injury and destruction as the thermometer one and others. 

 On the top of the stove should be placed a broad ^tin pan containing 

 water, the evaporation of which is necessary for the health of the 

 plants under the operation of the stove, as the air would otherwise be 

 rarified too much.* The fuel I use is Welch stone coal, (I believe 

 a description of anthracite,) such as is burnt in malt-kiln fires, and 

 this I rind from long experience to be the best for closed stoves. It 

 should be broken in pieces from the size of an egg to that of the 

 fist, or even larger, but by no means use small coal or coke for a 

 night-fire, as the former chokes the draught immediately, and the 

 latter in a short time, by being sooner reduced to ashes than almost 

 any hard fuel ; and the effect would be, that the air for feeding com- 

 bustion (all of which must come from the ash-pit through the grating) 

 would be excluded, and. of course, the fire go out. The stone coal 

 makes very little ash or cinder, and produces very little gas to cause 

 smoke that may choke the flue. One of the most particular things 

 to attend to in themanagement of the Arnott stove, is, raking the 

 ashes from the grating the last thing at night; I manage it with a 

 single tooth iron rake, which will pass freely through the bar of the 

 grating, the bars of course ranging in a direction to and from the 

 door. 



* The propriety of keeping " a large open tank of water" in a greenhouse, as 

 described by " A. B. C," appears very questionable, particulaily when heat is 

 not applied, as it may cause damp and mildew. 



