134 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



NOTE ON ELECTRIC HEATING. 

 By R. B. Rogers, A.M.Inst.C.E., F.R.H.S. 



I find electric power a very useful and not at all expensive way of getting 

 a little extra heat locally in a conservatory. In the corner of nay con- 

 servatory I have an octagonal hand-light standing on an octagonal 

 wooden frame, 1 ft. 3 in. deep and 1 ft. length of side, in which I have a 

 few Orchids, and it is also useful for bringing on seedling Ferns or any- 

 thing else which requires a close warm atmosphere. With two 8-candle- 

 power 110-volt lamps working on a 100-volt circuit I can keep the 

 temperature inside 10° to 12° above that outside. Either lamp can be 

 used separately or both together. The bottom is made of two sheets of 

 flat galvanised iron, one above the other, with some small flat stones 

 between : this is to prevent loss of heat downwards. The lower sheet 

 lies on the staging. The lamps lie on the galvanised iron and are covered 

 by flat tins ; over these are two slates, one over the other ; then a pot can 

 stand on the top without risk of overheating the bottom of the pot. The 

 current is taken to the lamps by twin lead -covered cable taken into the 

 lampholder and the back of the lampholder filled with insulating com- 

 pound. The insulation is low, due no doubt to leakage from the lamp- 

 holders ; but there is no risk of fire, as they are entirely surrounded by 

 stone and metal. 



I have also arranged an electrically heated hotbed. This consists of 

 a round galvanised iron vessel, 7 in. deep and 16 in. diameter, filled 

 with leaf mould in which the pots are plunged. This rests on a cylinder 

 of sheet iron, 7 in. deep, standing on a wooden platform. In this platform 

 there is a square hole, in which a tray fits, carrying the lamp ; the 

 bottom of this tray is covered with sand. The sheet-iron cylinder is 

 surrounded with sand, and the hotbed itself is surrounded with wood- 

 wool and sawdust ; there is a wooden casing outside to hold the sand, Sec. 

 Over the hotbed there is an octagonal hand-light. With one 8-candle- 

 power 110-volt lamp on 100-volt circuit the temperature is about 90 u 

 8 in. below the surface. From these experiments it will be seen that very 

 little power is required to heat a small enclosure provided the heat is 

 properly kept in, and it seems to me a very convenient and cheap way of 

 heating enclosed window boxes, or any small enclosure in a sitting-room. 

 I have three landholders fixed under the staging in my conservatory in 

 which I can put 32-candle power lamps to get a little extra heat in very 

 cold weather ; but to heat a whole house electrically would of course take a 

 good deal more power ; and although it would be more easily under control 

 than any other way of heating it might be too expensive. 



