58 



OH THE MERITS OF IRON AND WOOD FOR ROOKS. 



in each figure : A is the furnace in which the fuel is placed, en- 

 tirely surrounded (except the under side) with the boiler ; B is 

 the check draft over which the heat, flame, and smoke passes to 

 a small aperture C in the back of the boiler communicating with 

 the flues D, surrounding the lower part which unite and pass 

 through an opening E in the flange on each side of the furnace 

 door to the flue F which surrounds the upper part, and termi- 

 nates at the brick flue G, furnished with a damper to regulate 

 the draft. 



The boiler H is in the form of an egg, on the plan with a 

 chamber all round connected with the check draft B and sur- 

 rounded with the flange or cover to flue I, with and iron cap L 

 either fixed or loose as may be required ; MM are two outlet 

 pipes communicating with the upper part of the boiler, through 

 which the hot water circulates. After passing to the outside of 

 the brick work, the pipes are ramified into two or three bran- 

 ches, if it is required, for warming different houses or separate 

 parts of the building; NN are two return pipes, which enter the 

 boiler ; is an ash pit with a door Q to regulate the draft of 

 the furnace as double doors ; P to exclude the external air. 

 Figure 5 is a section of boiler, with an additional flue sur- 

 rounding the lower part. 



