( 



170 HEATING AS APPLIED IN HORTICULTURE. 



nal boiler extends from within 8 inches of 

 the grating on which the fuel burns to the 

 top of the dome ; it is connected at 

 its base with the external boiler by 



Fig. 199. Fig. 200. 



two pipes, and also has free commu- 

 nication with it at the top. The two 

 boilers are separated from each other by 

 a space of about 2 inches, and the fire 

 acts upon both in a very equal degree. 

 The flow-pipe proceeds from the top, as 

 in the conical boiler, and the return-pipe 

 enters at the bottom, while the pipe for 

 conveying away the smoke is placed at 

 one side. This boiler is made of copper, 

 and is portable, so that it can be removed 

 when not in use ; and it has the peculiar 

 merit of requiring no setting or brick- 

 work. It is also considered by Messrs 

 Stephenson to consume its own smoke 

 better than most others. The consump- 

 tion of smoke, it should, however, be 

 observed, in all similar furnaces, depends 

 very much upon the management of the 

 fire. Fig. 199 is an elevation of the boiler ; 

 a and d are brass unions which connect 

 the boiler with the pipes, a being] the 

 flow, and d the return, b is the smoke- 

 pipe, which may be continued to any 

 required height, and carried in any direc- 

 tion most convenient for the escape of 

 the smoke. c is the movable dome 

 through which the fire is supplied with 

 fuel, e is an iron stand with revolving 

 grating bars, for the convenient removal 

 of clinkers, ashes, &c. ; / the ash-hole. 

 Fig. 200 is a vertical section of the same 

 boiler. The letters of reference apply as 

 in the last figure ; a, shown on this one 

 alone, is a hopper for fuel. 



/Stephenson's improved conical boiler is 



placed on a stand connected with two 

 branches of pipes. Thus one boiler may 

 be used to heat several buildings, either 

 together or separately, the distribution 

 of the heat being regulated by a stop- 

 valve fixed to each leading pipe. The 

 boilers can be connected with pipes of 

 any diameter by small iron or leaden 

 pipes. 



Fig. 201 is a geometrical elevation of 

 this boiler : a and d are brass unions 

 which connect with small pipes ; b is the 

 smoke-pipe ; c is the door for fuel ; e is 

 an iron stand with revolving grating, as 

 in the cylindrical boiler last noticed. 



Fig. 202 is a vertical section, showing 

 the fuel resting on the grating bars, the 



Fig. 201. Fig. 202. 



smoke escaping at b. The arrows indicate 

 the water-way entirely surrounding the 

 ignited fuel. 



Wood <Sf Co.'s improved copper conical 

 boiler — fig. 203. — This apparatus differs 



Fig. 203. 



from most others in respect of a greater 

 quantity of pipes being used, and this 

 we are disposed to consider a merit. It 

 may be detached from the pipes when 

 required, as they are connected by union 

 screws. It wastes but little water, there- 

 fore a small cistern only is required. 

 The pipe which connects the cistern with 



