About the close of the last century the great improvement in the manufacture of bar-iron was introduced by passing it through grooved rollers, instead of hammering it on the anvil; but in our own time the invention has become most important. The inventor, Mr. Coet, spent a fortune on the enterprise and died poor. His son, in 1812, petitioned Parliament to assign him some reward for the great gift that his father had bestowed upon the nation. He asked in vain. It is the common fate of the ingenious and the learned; and it is well that life has some other consolations for the man that has exercised his intellect more profitably for the world than for himself, than the pride of the mere capitalist, who thinks accumulation, and accumulation only, the chief business of existence. Rolling bar-iron is one of the great labour-saving principles that especially prevail in every branch of manufacture in metals. The unaided strength of all the men in Britain could not make all the iron which is at present made, though they did nothing else. Machinery is therefore resorted to; and water-wheels, steam-engines, and all sorts of powers are set to work in moving hammers, turning rollers, and drawing rods and wires through holes, till every workman can have the particular form which he wants. If it were not for the machinery that is employed in the manufacture, no man could obtain a spade for less than the price of a year's labour; the yokes of a horse would cost more than the horse himself; and the farmer would have to return to wooden plough-shares, and hoes made of sticks with crooked ends. After all this, the iron is not yet fit for a knife, at least for such a knife as an Englishman may buy for a shilling. Many nations would, however, be thankful for a little bit of it, and nations too in whose countries there is no want of iron-ore. But they have no knowledge of the method of making iron, and have no furnaces or machinery. When our ships sail among the people of the eastern islands, those people do not ask for gold. "Iron, iron!" is the call; and he who can exchange his best commodity for a rusty nail or a bit of iron hoop is a fortunate individual. We are not satisfied with that in the best form, which is a treasure to those people in the worst. We must have a knife, not of iron, but of _steel_,--a substance that will bear a keen edge without either breaking or bending. In order to get that, we must again change the nature of our material. How is that to be done? The oftener that iron is heated and hammered, it becomes the softer and more ductile; and as the heating and hammering forced the carbon out of it, if we give it the carbon back again, we shall harden it; but it happens that we also give it other properties, by restoring its carbon, when the iron has once been in a ductile state.