118 



THE DICTIONARY OF GARDENING, 



Heating continued. 



one end, or even inside a house, as no bricks are required 

 for setting, and the smoke may be conducted from the flue 

 to the outside by a circular pipe or chimney. The exterior 

 view of these independent boilers presents a neat appear- 

 ance; but it ia not advisable to place them inside the 



FIG. 177. UPRIGHT CYLINDER BOILER. VERTICAL SECTION. 



a, Flow Pipe ; 6, Return Pipe ; c, Fire Door ; d, Ash-box Door, 

 with Ventilator ; e, Smoke Flue. 



plant house if it can be avoided, on account of their 

 drying effect on the air. Independent cylinder boilers 

 are made both with and without an extended top for 

 adding fresh fuel. 



Small greenhouses are occasionally heated with boilers 

 warmed by gas instead of ordinary fuel. This method is 

 rather expensive to keep sufficient water in circulation 

 for raising or maintaining a medium temperature in a 

 large glass house. It is, however, a convenient mode of 

 excluding frost from small structures in places where a 



FIG. 178. WRIGHT AND Co.'s GAS BOILER. 



a, Boiler, consisting of Heating Coil, inclosed in a case ; 6, Con- 



nection of Burners with Gas-pipe ; c, Flow Pipe ; d, Return Pipe. 



plentiful supply of gas can be obtained. It has an ad- 

 vantage for those who do not require much heat, and 



Heating 1 continued. 



who are unable to attend to fires. When once started 

 at the proper rate, the water will continue to warm and 

 circulate so long as the gas keeps burning. A little 

 additional water is necessary in the supply cistern occa- 

 sionally. Gas boilers, of which Messrs. Wright and Co.'s 

 is a good arrangement (see Fig. 178), consist of a heating 

 coil of pipes arranged above one or more Bunsen burners 

 inside an inclosed case, and having a flow pipe attached, 

 which branches into another, as shown in the illustration, 

 and returns to the lower part of the boiler. With a small 

 flue attached, the whole apparatus can stand in the house 

 it has to warm, and thus the full amount of heat will 

 be utilised. The product of combustion from a Bunsen 

 burner is merely a slight vapour, sufficient oxygen being 

 incorporated with the gas, so soon as it leaves the pipe, 

 to cause its whole consumption by the fire without any 

 soot being left. Two stoves heated by gas, and answering 



FIG. 179. RITCHIE'S Lux CALOR, 



A, Door, which opens on a Bunsen burner ; B, B, Tubes, in which 

 the products of combustion are condensed (with the exception of 

 the carbonic acid) into fluid form. 



without flues, are Ritchie's Lux Calor (see Fig. 179) and 

 Clark's Syphon Condensing Stove, represented in Fig. 180 ; 

 both having Bunsen burners attached. In the Lux Calor, 

 the products of combustion, with the exception of carbonic 

 acid, are condensed in tubes on either side of the burner. 



FIG. 180. CLARK'S SYPHON CONDENSING STOVE. 



There is little fear of the small amount of carbonic acid 

 gas doing injury, as, being heavier than atmospheric air, 

 it falls to the lowest point, and is removed by any feeble 

 current. This stove is calculated to warm any fairly 

 good structure, not too much exposed, with an interior 

 capacity not exceeding 1000 cubic feet. The Syphon 

 Condensing Stove is constructed on somewhat the same 

 lines as the Lux Calor; but, unlike it, the warm air is 

 after parting with the products of combustion conveyed 

 through a tube over the flame and into the space to be 



