ROl MBLE ENGINEERING 9 



The boiler is tapped in from two to four places for the 



>cks, the location of the cocks ranging from a line 



.ibove the level of the crown sheet, or top of fire 



box, to eight inches above, depending somewhat on the 



amount r space above the licet, as this 



c differs very material!;. ierent makes of the 



same s : /cd boiler. The boiler is also tapped on or near 



the level of the crown sheet, to receive the lower water 



glass CCK : >o\e this, for the top code The 



space Ix-tween shows the safe variation of the water. 



Don't let the water get above the top of the glass, for if 



you are running your engine at hard work, you may 



knock out a cylinder he;: lon't let it get below the 



lower gauge, or you may get your own head knocked off. 



Now the glass gauge is put on for your convenience, 

 as you can determine the location of the water as cor- 

 rectly by this as if you were looking directly into the 

 boiler, provided the glass gauge is in perfect order, 

 icre are a number of ways in which it may be- 

 come disarranged or unreliable, we want to impress on 

 your mind that you must not depend on it entirely. We 

 will give these causes further on. You are not only 

 provided with the glass gauge, but with the try-cocks. 

 These cocks are located so that the upper and lower cock 

 i or near the level with the lower and upper end of 

 the glass gauge. With another try -cock about on a level 



