52 Construction of Fire-places to Steam Boilers. [July, 



which is in contact with the fire, is terminated by Welch or 

 Stourbridge lumps. Under it a small door is placed, which 

 serves to permit the introduction of a bar to break up the fire 

 occasionally, or to cut out the clinkers. 



The furnace is further provided with apertures for the intro- 

 duction of air, so as to consume the smoke, the situation of 

 which may be observed in the two sections. In the lateral one 

 may be seen where two enter the furnace on one side; the 

 number may of course be increased at the option of the builder ; 

 and in the transverse section, the mode of conducting the air 

 is exhibited. 



It has been very judiciously observed that when cold air is 

 admitted in a direction parallel to the current of the smoke, it 

 frequently passes with it into the chimney without inflaming it, 

 the two streams running as it were together without mixing in 

 such a manner as is required to produce the effect. To have 

 the inflammation complete, the air should be as hot as possible, 

 by which also the least check is given to the action of the fire, 

 and the current shoidd cross that of the smoke where (hey meet, 

 by which such a mixture of the two is produced as is required 

 for the intended purpose. 



The air in this furnace is first admitted by small passages in 

 its sides, which are fitted with registers, ana passes horizontally 

 so as to strike against the back of the fire-bricks lining the fire- 

 place, behind which it rises until it is turned through small aper- 

 tures into the furnace. The vertical passages may be extended 

 considerably in a lateral direction, so as to present a great heating 

 surface to the air, which also will serve to increase the durabi- 

 lity of the fire-bricks by keeping them cooled at the back. The 

 air enters so as to cross the current of the draft ; and the opening 

 into the fire is so made as to direct the influx towards the centre, 

 and to prevent it from striking the arch, which otherwise would 

 be injured by it. The quantity of air is regulated at pleasure by 

 the registers ; and it is obvious that it will always pass into the 

 fire in a heated state, which seems to be essential to the speedy 

 inflammation of the smoke. We are, Sec. &c. 



John and Philip Taylor. 



Description of the Plate. 



Fig. 1. Lateral section, showing the furnace or fire-place, and 

 one end of a long steam boiler, under which the flame passea 

 through a semicircular flue to the chimney at the other end. 



A, fire-place. 



B, ash-pit. 



C, throat of the furnace. 



D, flue under the boiler. 



E, the boiler. 



a, the hopper for coals. 



