252 SCHEELITE IN NOVA SCOTIA. McCALLUM. 



to say that it will assist carbon in producing hardness and 

 therefore high tungsten steels may have a lower carbon. 



!N"o amount of tungsten or any other element will make steel 

 hard in the absence of carbon or even when the carbon is low. 

 The tungsten produces hardness by its effect on the condition of 

 the carbon ; that is, by helping to retain the carbon in its solid 

 solution and not by any effect of its own. It is for this reason 

 that a lesser amount of carbon will produce hardness in the 

 presence of tungsten or other similar element. 



A variety of bronze-powder is made by fusing potassium, 

 tungstate and tin. It is also used for coloring glass and as a 

 glaze for porcelain. Eecently metallic tungsten is being used 

 extensively in the manufacture of incandescent electric lamps. 

 It is claimed that it uses only one-third the amount of current 

 required by a carbon lamp, and that it maintains its rated 

 candle power for 1,000 hours. 



