WITti VARIOUS FUELS. 31 



so that the flames can pass freely between them. The real* 

 dirait door Should be opened wide and the front one opened 

 only enough to admit sufficient air. See that the front end 

 of the grates (next to the tube sheet) is kept well covered. 

 If cold air be allowed to pass through to the tubes at this 

 point, the draft will be destroyed. To get satisfactory results, 

 it is often necessary to cover the front end of the grates, for 

 a space of eight inches, with a "dead-plate." A wood fire 

 requires an occasional "knocking-down," but as with coal it 

 is a good plan not to use the poker more than is absolutely 

 necessary. In "knocking-down" do not disturb the hot 

 coals on the grates. In firing with wood it is advisable to 

 keep the screen in the smoke-stack down as there is more 

 danger of setting fire with wood than with coal. 



Firing with Straw. Modern "Case" straw burning en- 

 gines are all of the direct flue type. They ate the same as 

 the coal burners, except that they are fitted with straw 

 grates, dead-plates, a brick arch and a straw chute and the 

 boiler is lagged. (See Fig. 6.) Any "Case" side-crank 

 spring-mounted engine, except the Nine-Horse, can be made 

 to burn straw by making these changes. 



When firing with straw, keep the chute full all the time, 

 so that no cold air can get in on top of the fire. Take small 

 forkfuls and let each bunch of straw push the preceding one 

 into the fire. Occasionally turn the fork over and run it in 

 below the straw in the chute to break down and level up the 

 fire. Three grates, spaced equally across the fire box, are 



