SLAG BRICKS.

[Stanley]

SLAG BRICKS.

In many of our northern towns you will see the crossings of the roads paved with large grey bricks, which have a dull but rather glossy surface, and are often faintly tinged with patches and streaks of blue. Round the middle or waist of each brick there is a groove which divides it into halves, and by means of this division we can see that the bricks are twice as long as their width. In order to form the pavement, the bricks may be laid close together either upon their sides or their ends, and when neatly laid, they present the appearance of a path of dull, grey, common tiles. They are rather brittle, and for this reason they are not used in streets where there is much heavy traffic; but narrow back streets, causeways, and little yards are frequently paved with them.

It is a very interesting sight to see these bricks made. In order to enjoy such a sight, we must make our way to one of the great blast-furnaces where iron is being smelted. Blast-furnaces are erected in pairs, and are huge towers in which intensely hot fires are kept continually burning. Into the top of the towers wagon-loads of coke, stony iron ore, and lime or limestone are being continually tipped ; and the heat is so great that all these materials are either
Burnt up or melted. In this operation the iron separates from the stony part of the ore, and since all the materials left in the furnace are in a fluid condition, and the melted iron is the heaviest of them, it flows to the bottom of the furnace. The waste of the ore and other materials forms a kind of melted stone, known as slag, which flows downwards, but, being lighter than the iron, stops when it reaches it, and floats upon the top of it. Much more slag than iron is formed, and as a great amount of heat is required to keep the slag melted, the iron-maker is glad to get rid of it from the furnace. In order to do this, he makes a hole in the side of the furnace, higher up than the melted iron
reaches, and allows the slag to flow away as it is formed. If you stand by the side of a blast furnace, you will see a little white-hot stream flowing from
its side, and passing along an iron trench or gutter. This trench divides into nine or ten smaller ones, each of which conveys a little rill of slag to an iron
box or can which resembles a very large milk-can. These cans stand upon railway trucks, and when they are filled the loaded truck is drawn away, and
another truck bearing empty cans is run into its place.

It is from this slag, the waste of the blast-furnace, that the bricks are made. The truck of full cans is led away by a locomotive to an open space at some distance, where there is a large iron wheel, twenty or thirty feet across, lying on its side. This wheel stands up two or three feet from the ground, and turns on an upright axle, All round the wheel there are a number of iron boxes, resembling so many cigar boxes set upright, a foot or so from each other, -with their lids turned outwards. Each box is the mould for one slag brick, and, of course, its interior is just the size and shape of a brick. The lid, or door, opens and closes by means of hinges at the side, and it is fastened with an iron latch, just like an oven door. Upon the top of the box there is a wide-mouthed iron funnel, which leads to the inside.

The truck, with its load of slag-cans, is brought close up to one edge of the wheel, and an iron trench is laid from one of the cans to a point just over one of the funnels. A hole is opened in the can, and the slag, which is still liquid, runs along the trench, and through the funnel into the box. The latter is soon full, and the slag begins to run over the funnel on to the ground. A boy gives the wheel a push, and another empty box is brought to the trench, and quickly filled. Again the wheel is pushed, and another box is filled, and this goes on until the box which was first filled has been pushed round to a point opposite the trench-until, in short, the wheel has received half a turn.

And now it is time to remove the brick from this box which was first filled. All the work is done by boys, and I can assure you that when I saw them they worked and talked like grown-up men. The boy who is to remove the brick is provided with a long pair of iron tongs. Using his tongs with great skill, he knocks up the iron latch, and draws back the door of the box.

The brick is set quite firm, though it is still red-hot, and the boy seizes it by the middle with his tongs, drags it from the box, and places it on an iron barrow. Then, with a few blows of the tongs, he knocks out the slag from the funnel, clears away any fragments which fall into the box, and closes and latches the door. All this is accomplished while one box at the other side of the wheel is filling; and when that box is full, and the wheel is moved, this expert lad is ready to empty the next box which comes round to him. The empty box passes on its way, and by-and-by comes round again to its starting-place, and receives another flow of slag.

The bricks, after being taken from the boxes, are conveyed to a kiln, where they are kept hot for a day or so, after which they are allowed to cool. This baking or annealing, as it is called, is necessary to make the bricks hard and compact. There is much waste of slag in the operations of brick-making, and many of the bricks do not set properly. But the sound bricks are very useful, and since they are made with little labour out of slag, which was formerly treated as waste, they can be sold at low prices.

W. A. ATKINSON.