Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. In many cases tool-steel is still more closely designated according to the smelting processes from which it has resulted, such as ingot-steel, weld-steel or according to the method of production, such as Bessemer steel, Martin steel, crucible steel, puddled steel, shear steel, etc.; further accord ing to certain peculiarities, such as natural or self-hardened steel, hard-centred steel, soft-centred or mild-centred steel, tungsten-steel, chrome-steel, nickel-steel, etc; and finally, according to the purposes to which it is to be applied, such as knife-steel, scythe-steel, magnet-steel, punch-steel, chisel steel, etc.