When a bar of wrought iron is broken by a weight being placed iippn it, it is supposed by many persons that the remaining parts are rendered weaker than they were before, on account of the, strain to which they have been subjected. This is a mistaken idea. Such pieces of iron b^s are generally stronger, according to their diameter, than they were before the bar was broken. The strain to which they have been subjected, by drawing the fibers' closer together, increases their density, and, as a consequence, the strength of the metal. A wire of one-eight of an inch in thickness is, proportionahly, stronger than one twice the thickness, simply because its iibres are packed closer together by the operation of drawing.