604 



J. 0. Arnold 



[Jan. -24, 



In connexion with the early importation of pure Swedish or 

 Spanish h-on for a basis metal, it is significant that in 1442 Sheffield 

 obtained a Eoyal warrant to construct tow-paths to make the River 

 Don navigable. This river runs into the Humber at Goole, and there 

 is little doubt that as early as the fifteenth century Sheffield steel- 

 makers were endeavouring to replace the costl}' pack-horse transit of 

 foreign raw materials by cheaper water carriage from the Humber. 

 It is next of interest to consider how, during the fourteenth, fifteenth, 

 sixteenth, seventeenth, and half the eighteenth centuries, Sheffield 

 made all its fine steel. It seems almost certain that the nearly pure 

 imported Swedish or Spanish irons were carburized " in the dry way " 

 by cementation in charcoal at a yellow heat. 



Brand of 

 Single Shear Steel. 



Brand of 

 Double Shear Steel, 



Fig. 1. 



The slide on the screen shows the highly ductile bar iron and the 

 blistered and brittle steel resulting from its cementation-carburization . 

 The blister bar was then made into what, for perhaps two hundred 

 and fifty years, has been known as " Shear Steel." 



The next slide shows the method of producing from lilister bar 

 both single and double shear steel. The origin of the name " shear 

 steel " was due to the fact that British cloth-workers insisted on 

 having this fine quality of steel for their cloth cutting shears, and 

 this material is still branded with rude representations of clothier's 

 shears, as shown by the slide on the screen (Fig. 1). One pair of 

 shears signifies single shear, and two pairs double shear steel. The 

 chemical composition of this steel, which is the purest made, is ex- 

 hibited on the screen. With its high reputation built up during 



