" Saws, sword-blades, clock and watch springs, etc, which, after being hardened and tempered, require to be ground and polished,or otherwise brightened, lose their elasticity or springiness by these operations, so as to appear soft on bending them, although they are as hard as ever; these qualities are again restored to them, either by heating over a clear fire, made of cinders urged by bellows, or over the flame of burning alcohol, or by inclosing them in a smouldering fire, made of wood-ashes and embers, to a blue colour, which colour may either remain, or be removed by the application of diluted muriatic acid wiped over them."

The partial Conversion of Iron into Steel, which is often the case in the blistered bars, owing to the carbon not having penetrated to the middle, is usually regarded as a great defect; but an important advantage may be gained from it in the steeling of edge-tools, which, Mr. Gill says, is adopted by Mr. Maudsley. The bar is split down its middle into two parts, and these parts are sometimes subdivided; the internal parts which remain unconverted are then welded to the iron of the tool, leaving the steel outside, to form the cutting edges of the tool.