8. What has caused the wonderfully increased production of Great Britain?

9. What has been the increase of production as compared with the increase of population?

10. What were the sole instruments of tillage at the beginning of this century?

11. What are the most striking differences between the agriculture at that time and at the present time?

12. Mention some of the most important machines now used in agriculture. 13. What is now the proportion of agriculturists to the entire population of Great Britain?

14. How much has that proportion decreased since the beginning of this century?

15. What has rendered such a result possible?

CHAPTER 'XII.

Production of a knife-Manufacture of iron-Raising coal-The hot-blastIron bridges Rolling bar-iron-Making steel-Sheffield manufactures— Mining in Great Britain-Numbers engaged in mines and metal manufac

tures.

WE E have been speaking somewhat fully of agricultural instruments and agricultural labour, because they are at the root of all other profitable industry. Bread and beef make the bone and sinew of the workman. Ploughs and harrows, and drills, and thrashing machines are combinations of wood and iron. Rude nations have wooden ploughs. Unless the English labourer made a plough out of two pieces of stick, and carried it upon his shoulder to the field, as the toil-worn and poor people of India do, he must have some iron about it. He cannot get iron without machinery. He cannot get even his knife, his tool of all-work, without machinery. From the first step to the last in the production of a knife, machinery and scientific appliances have done the chief work. People that have no science and no machinery sharpen a stone, or a bit of shell or bone, and cut or saw with it in the best way they can; and after they have become very clever, they fasten it to a wooden handle with a cord of bark. An Englishman examines two or three dozens of knives, selects which he thinks the best, and pays a shilling for it, the seller thanking him for his custom. The man who has nothing but the bone or the shell would gladly toil a month for that which does not cost an English labourer half a day's wages.

And how does the Englishman obtain his knife upon

such easy terms? From the very same cause that he obtains all his other accommodations cheaper, in comparison with the ordinary wages of labour, than the inhabitant of most other countries—that is, from the operations of science, either in the making of the thing itself, or in procuring that without which it could not be made. We must always remember that, if we could not get the materials without scientific application, it would be impossible for us to get what is made of those materials—even if we had the power of fashioning those materials by the rudest labour.

Keeping this in mind, let us see how a knife could be obtained by a man who had nothing to depend on 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 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.

worse.

In the ordinary mode of using it, fire would make matters If we put the material into the fire as a stone, we should probably receive it back as slag or dross. We must, therefore, prepare our fuel. Our fire must be hot, very hot; but if our fuel be wood we must burn it into charcoal, or if it be coal into coke.

The charcoal, or coke, answers for one purpose; but we have still the clay or other earth mixed with our iron, and how are we to get rid of that? Pure clay, or pure lime, or pure earth of flint, remains stubborn in our hottest fires; but when they are mixed in a proper proportion, the one melts the other.

So charcoal or coke, and iron-stone or iron-ore, and limestone, are put into a furnace; the charcoal or coke is lighted at the bottom, and wind is blown into the furnace, at the bottom also. If that wind is not sent in by machinery, and very powerful machinery too, the effect will be little, and the work of the man great; but still it can be done.

In this furnace the lime and clay, or earth of flint, unite, and form a sort of glass, which floats upon the surface. At the same time the carbon, or pure charcoal, of the fuel, with the assistance of the limestone, mixes with the stone, or ore, and melts the iron, which, being heavier than the other matters, runs down to the bottom of the furnace, and remains there till the workman lets it out by a hole made at the bottom of the furnace for that purpose, and plugged with sand. When the workman knows there is enough melted, or when the appointed time arrives, he displaces the plug of sand with an iron rod, and the melted iron runs out like water, and is conveyed into furrows made in sand, where it cools, and the pieces formed in the principal furrows are called "sows," and those in the furrows branching from them "pigs."

We are now advanced a considerable way towards the production of a knife. We have the materials of a knife. We have the iron extracted out of the iron-ore. Before we trace the progress of a knife to its final polish, let us see what stupendous efforts of machinery have been required to produce the cast iron.

In every part of the operation of making iron-in smelting the iron out of the ore; in moulding cast iron into those articles for which it is best adapted; in working malleable iron, and in applying it to use after it is made; nothing can be done without fire, and the fuel that is used in almost every stage of the business is coal. The coal trade and the iron trade are thus so intimately connected, so very much dependent upon each other, that neither of them could be carried on to any extent without the other. The coal-mines supply fuel, and the iron-works give mining tools, pumps, railroads, wheels, and steam-engines, in return. A little coal might be got without the iron engines, and a little iron might be made without coals, by the charcoal of wood. But the quantity of both would be trifling in comparison. The wonderful amount of the production of iron in Great Britain, and the cheapness of iron, as com