MODERN BLACKSMITHING 131 



too full with dirty water; if it is it is best to blow off a 

 little. Foul water can be cleaned by different meth- 

 ods before it enters the boiler, so as to prevent foam- 

 ing and scaling. 



BLOWING OUT THE BOILER 



A boiler should not be blowed out under a high 

 steam pressure, because the change is so sudden that 

 it has a tendency to contract the iron, and if repeated 

 often the boiler will leak. If it is done when there is 

 brickwork around the boiler and the same is hot it will 

 in a short time ruin the boiler. In such a case the 

 boiler should not be blowed out for hours after you 

 have ceased firing. 



