le fuel, when introduced at the fire-door A, should be laid on 

 that part of the grate nearest to the fire-door, called the dead 

 plates : there it is submitted to the process of coking, by which 

 the gases and volatile matter which it contains are expelled, and 



Fig. 7. 



being carried by a current of air admitted through small apertures 

 in the fire-door over the burning fuel in the hinder part of the 

 grate, they are burnt. When the fuel in front of the grate has 

 been thus coked, it is pushed back, and a fresh feed introduced in 

 front. The coal thus pushed back soon becomes vividly ignited, 

 and by continuing this process, the fuel spread over the grate is 

 maintained in the most active state of combustion at the hinder 

 part of the grate. By such an arrangement, the smoke produced 

 by the combustion of the fuel may be burnt before it enters the 



12 





