432 Directions for Worhing Portable Steani-Engines. 



wnj open till the coal is ignited ; coal may then be put on in 

 small quantities at a time, the fire-bars being kept covered to a 

 depth not exceeding three inches ; the fire must be clear, but the 

 Ijars must not be allowed to become bare of coal in places, for 

 the cold air will then pass through the tubes and check the 

 formation of steam ; all wet straw and damp wood should bo 

 avoided for lisrhtino: the fire. As soon as the fire is lighted a few 

 pails of water should be poured into the ash-pan ; it tends to 

 prevent the formation of clinkers, and greatly preserves the fire- 

 bars by keeping them cool ; it also decreases the danger of fire in 

 the stack-yard, because all the hot cinders, as they fall from the 

 grate, are instantly extinguished ; if the weather be very windy, it 

 may be necessary to close one of the doors of the ash-pan, and to 

 open the other; experience will soon point out which door should 

 b;* closed. 



Eaising Steam. 

 The fire, as it burns up, should be kept thin and bright ; the 

 coal must never be heaped up against the tubes ;. too much coal 

 should not be thrown on at a time, or it will tend to delay the 

 ])roduction of steam ; a careful engine-man will soon find out the 

 best mode of firing with the different descriptions of coal he will 

 l)e required to use. 



Brushincj out Tubes. 

 If the coal is bad, or of a kind which emits a large quantity 

 of smoke, the tubes should be well brushed out during the dinner 

 hour ; this can easily be done without dropping the fire, by 

 allowing it to burn low, and raking it into one corner of the 

 grate. The tubes may be easily brushed out from the smoke- 

 box end. Before commencing to light the fire in the morning, 

 the tubes must always be well brushed out. 



Safety-Valve and Spring-Balance. 

 As soon as the water begins to boil, the safety-valve should be 

 opened by hand and examined, to make sure that it "is not 

 obstructed in any way ; the spring-balance may then be screwed, 

 down to about 10 lb., and wlien the steam blows off at that point 

 it may be gradually screwed down to 45 or 50 lb. as the steam 

 rises. The spring-balance should on no account be left always 

 screwed down to the full pressure when the engine is not at 

 work, and the steam not up, because the elasticity of the spring 

 is thus destroyed ; and it is very possible, if the engine remains 

 long out of use, that the valve may l^ecome set fast, Avhich would 

 cause danger when the steam was next got up. 



Oiling the Engine, 

 Before starting put a little oil into the cylinder through the 



