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the operator to make it hold the heat for some time after it was removed 

 from the crucible. In this case the continued blowing with the cold air 

 would save the use of a forge fire, and a second heating of the scraps of 

 iron, and thus economise trouble and expense in their manipulation. 



I may now describe the process for burning iron partially, used by 

 the makers of horse-shoe nails in Dublin and elsewhere. The nail-rod 

 is heated in the common forge fire, like any other nail-rod iron ; but, in- 

 stead of being at once submitted to the action of the hammer, it is placed 

 on the anvil so that the heated part of the iron rod overhangs its face 

 on one side. In this position it is exposed for some seconds to a power- 

 ful and steady blast of cold air, obtained from a circular bellows, very 

 Asiatic in its character and form. This bellows gives a much greater 

 blast than that used for blowing the fire, due to the greater load placed 

 upon it, which gives a pressure, at the least, of twenty-five pounds to 

 the superficial foot. This may be increased by pressure from the hand 

 of the nailer, who watches the burning of the iron till he thinks it has 

 gone far enough, and then he places the burning iron on the face of the 

 anvil, keeping it more or less in the blast while he hammers it hot. 

 Thus it appears that the usual aphorisms, which apply to the making of 

 nails in a hurry, do not refer to this process at all. 



The heated nail -rod, instead of getting cold by the action of the blast, 

 gets hotter and hotter, and burns partially, throwing ofi:' innumerable 

 small sparks, which pass ofi" in all directions, their courses not being in- 

 fluenced by the direction of the blast. Scales or small slags form on the 

 hot iron, which are believed to consist chiefly of impurities in the nail- 

 rod. At last the iron begins to melt, and would drop doAvn like melted 

 sealing-wax, if not removed from the direct influence of the blast, as de- 

 scribed. By moving the iron more or less into the blast, the nailer is 

 able to moderate and regulate the heat of the portion he is operating on ; 

 and this enables him to complete the point and shank of the horse-shoe 

 nail hot, and before any crystallization of the iron begins or is com- 

 pleted, which it is by the hammering and hardening of the common 

 nail when nearly cold. In theory, the nailer's process of blowing the 

 iron of a horse-shoe nail is perfect, for it enables him to make the point 

 and shank of the nail as soft and tough as he likes, while it allows him 

 to make the head of it very hard, and thus withstand the friction to 

 which it is exposed by its contact with the road. 



The operation of making a horse-shoe nail by the cold blast process, 

 beyond a doubt, gives the iron it is composed of some characters, both 

 chemical and organic, very difi'erent to those possessed by the nail-rod 

 previously. It clearly brings horse- shoe nail iron up to the Damascus 

 standard, in many respects, and may place it above both the Japanese 

 and Bessemer iron, prepared by the cold blast, as it is manipulated on 

 a much smaller scale, and consequently is more completely exposed to 

 the purifying action of the blast. 



In the arts many applications of the nailer's cold blast process might 

 be found, in cases where it would be expedient to keep iron hot without 

 the immediate application of fuel. In rivet work it might be found most 



