THE FEED WATER. 15 



Do not attempt to pull it out, as stirring it up creates intense 

 heat. Having banked the fire, leave the engine alone until 

 the steam goes down. By doing this, you have probably 

 prevented the fusible plug from melting, or, what is vastly 

 more serious, burning the crown-sheet. A crown-sheet that 

 has been burnt is greatly weakened, probably "bagged" or 

 warped, and the stay-bolts -so strained at their threads that 

 it is impossible to keep them from leaking. The majority 

 of explosions of boilers of the locomotive type are caused 

 by low water and the consequent burning of the crown-sheet. 

 One experience with low water should be a sufficient lesson 

 for all time. 



Since so much depends upon having sufficient water in 

 the boiler, the gage-cocks and water-glass, which indicate 

 the amount of water, should be kept in first-class order. 



The Gage-Cocks. These cocks are a more reliable 

 means of indicating the amount of water in the boiler than 

 the water-glass, although not so convenient. The gage- 

 cocks, or "try-cocks," as they are sometimes called, should 

 be used often enough to prevent them from becoming filled 

 with lime and should always be in working order. When- 

 ever opened, the steam should be allowed to blow through 

 a sufficient time to clean them. They should then be closed 

 moderately tight, and then, if they leak, they should be 

 opened again to allow any dirt or scale that may have lodged 

 on the seat to blow out. It is not well to force a gage-cock 

 or other valve shut to stop it from leaking, for probably it 



