THE BOILER. 9 1 



a chance to soften with the heat and adapt itself to the iron 

 surfaces. 



Cleaning the Tubes. The tubes should be cleaned at 

 least once each day, whether in burning coal, wood or straw. 

 The tube scraper is adjustable, and may be set out while 

 in the tube by turning the rod to the right. Turning the rod 

 to the left decreases the size of the scraper. Soot is a very 

 poor conductor of heat, and even a thin coating of it affects 

 the efficiency of the boiler to a considerable extent. It is 

 therefore, essential to keep the scraper well set out, so that 

 all the soot will be removed. 



Expanding and Beading the Tubes. Leaky tubes should 

 be fixed the first time the engine cools. When the steam no 

 longer shows on the gage, remove the ash-pan bottom and 

 grates ; also the bricks, if the engine be a straw burner. If 

 the leaks be only slight ones, they may be stopped by simply 

 using a beading tool. To do this clean the end of the tube 

 and the tube sheet and place the long or guiding end of the 

 tool within the tube. Use a small hammer, and with light 

 blows bead the tube all around, moving the tool slightly at 

 each blow. The beading tool may be used when there is 

 water in the boiler, but care must be taken to use only very 

 light blows of the hammer or the concussion will be trans- 

 mitted by the water and loosen other tubes. Having water 

 in the boiler when beading the tubes has the advantage of 

 showing the leaks so that it may be known when the tube is 

 tight. If the leaks be more serious, it will be necessary to 



