[Sidenote: 21. Cotton Spinning.] Let us glance for just a moment at this larger mill, at this wool-spinning room, and at this cotton-spinning room. They require no further description, for they merely differ in scale from those we have already studied. [Sidenote: 22. Glass Blowing.] [Sidenote: 23. Glass Blowing.] And now we will turn from the making of textiles, which employs several millions of the inhabitants of Britain, and gives rise to perhaps the largest single trade of Britain, the cotton trade. Let us turn from that to consider the other great group of the industries, those which are based essentially on the melting of metals by the heat got from coal. One of the simplest and one of the oldest forms of this is the making and blowing of glass. It is true that glass is not a metal, but for industrial purposes it has many properties somewhat similar to those of metals. It can be melted, for instance, and worked while hot. Here we have a man engaged in blowing glass which has been melted by the use of coal. And here, when he has blown the bottle, he is shaping it with tools. [Sidenote: 24. Pottery making.] [Sidenote: 25. Pottery making.] A somewhat similar industry, although not involving the melting of the material in the first instance, is the making of pottery. Pottery was formerly made in the homes of the people, and the potter’s wheel was worked by the foot, as it still is in the East. But nowadays the wheels upon which the pots are shaped are driven by steam. Here we have women at work upon pottery. And in the next slide are men engaged upon a similar process, but their tools are driven by the foot. The pottery that is being made in this instance is of the costly kind, which is produced in small quantity, and demands artistic labour. It requires so little power that it is not worth while to drive the machinery by steam. In large measure steam has not replaced human skill for the very finest work. But the most important by far of the industries which are based on the use of coal for the melting of the raw material are those which deal with iron and steel. [Sidenote: 26. Blast Furnace.] [Sidenote: 27. Rolling Steel.] Here we have a group of blast furnaces, where the iron ore is mixed with coal and burnt. The molten iron flows out from the bottom of the furnace and cools into long blocks known as “pigs.” It would be impossible to show all the processes through which the pig iron is passed in the manufacture of the many wares made of iron and steel. Let us glance at a very few. Here we have a man inserting a white-hot, thick, short block of metal into a machine. He will lift it from that plate with his pincers and will insert it under the roller. The roller, crushing it, will reduce it in thickness and will greatly elongate it to this hot flexible rope. When cold, a steel rod will be the result. [Sidenote: 28. Making an Armour Plate.]