Keeping this in mind, let us see how a knife could be obtained by a man who had nothing to depend upon but his hands.
Ready-made, without the labour of some other man, a knife does not exist; but the iron, of which the knife is made, is to be had. Very little iron has ever been found in a native state, or fit for the blacksmith. The little that has been found in that state has been found only very lately; and if human art had not been able to procure any in addition to that, gold would have been cheap as compared with iron.
Iron is, no doubt, very abundant in nature; but it is always mixed with some other substance that not only renders it unfit for use, but hides its qualities. It is found in the state of what is called _iron-stone_, or _iron-ore_. Sometimes it is mixed with clay, at other times with lime or with the earth of flint; and there are also cases in which it is mixed with sulphur. In short, in the state in which iron is frequently met with, it is a much more likely substance to be chosen for paving a road, or building a wall, than for making a knife.
But suppose that the man knows the particular ore or stone that contains the iron, how is he to get it out? Mere force will not do, for the iron and the clay, or other substance, are so nicely mixed, that, though the ore were ground to the finest powder, the grinder is no nearer the iron than when he had a lump of a ton weight.
A man who has a block of wood has a wooden bowl in the heart of it; and he can get it out too by labour. The knife will do it for him in time; and if he take it to the turner, the turner with his machinery, his lathe, and his gouge, will work it out for him in half an hour. The man who has a lump of iron-ore has just as certainly a knife in the heart of it; but no mere labour can work it out. Shape it as he may, it is not a knife, or steel, or even iron--it is iron-ore; and dress it as he will, it would not cut better than a brickbat--certainly not so well as the shell or bone of the savage.
There must be knowledge before anything can be done in this case. We must know what is mixed with the iron, and how to separate it. We cannot do it by mere labour, as we can chip away the wood and get out the bowl; and therefore we have recourse to fire.