1^4 MODERN BLACKSMITHING 



coagulate if it is held against the fire so it gets warm. 

 Be careful with this powder, as it is a strong poison. 

 It is the best thing that I have ever tried for case hard- 

 ening iron. It will case harden the softest iron so that 

 it cannot be touched with any tool. It is also good for 

 plows, especially where it is hard to make a plow 

 scour. The only objection is the price, as it costs more 

 than prussiate of potash or other hardening com- 

 pounds. 



HOW TO HARDEN SPRINGS 



Heat to a heat that will be discerned in the dark as 

 a low red heat. Plunge into a bath of lukewarm 

 water. Such a heat cannot be noticed in a light sunny 

 day, but it is just the heat required. Of course, it is 

 the smith with practice who succeeds, as with every- 

 thing else. 



Another way: Heat to a low red heat and bury the 

 spring in cold sand. Another : Heat to a low red heat 

 in the dark, and cool in oil. 



TO MAKE STEEL AND IRON AS WHITE AS 



SILVER 



Take i pound of ashes from white ash bark, dissolve 

 in soft water. Heat your iron red, and cool in this 

 solution, and the iron will turn white as silver. 



