Scientific amusements . passing it betweenrollers, which flatten it, and thenbetween a new set, which formcutting edges on the rolled plate,the projections of one set fit-ting into the hollows of the wire rollers. other closely as in the two illustrations on this strips of metal come out at the aperture seen at A, inillustration on next page. These rods are drawn througha series of diminishing holes in a steel plate,occasionally being heated to keep it soft andductile. When the wire has got to a certainfineness it is attached to a cylinder anddrawn away, at the same time being woundro
Scientific amusements . passing it betweenrollers, which flatten it, and thenbetween a new set, which formcutting edges on the rolled plate,the projections of one set fit-ting into the hollows of the wire rollers. other closely as in the two illustrations on this strips of metal come out at the aperture seen at A, inillustration on next page. These rods are drawn througha series of diminishing holes in a steel plate,occasionally being heated to keep it soft andductile. When the wire has got to a certainfineness it is attached to a cylinder anddrawn away, at the same time being woundround the cylinder over a small fire. Somemetals can be drawn much finer than wire can be obtained of a thickness (or thinness) of only the 5,000th part of anJiJ inch, 550 feet weighing one grain! ButCutting edges. platiuum has exceeded this marvellous thin-ness, and wire the 30,000th part of an inch has beenproduced. Ductility and malleability are not alwaysfpund in the same metal in proportion. The sizes of. I40 CHEMISTRY. wires are gauged by the instrument shown in the margin. The farther the wire will go intothe groove the smaller its contains a certainamount of carbon, generallyabout Ito 2 is prepared from cast iron. Steelfrom bar-iron has carbon added,and is termed bar-steel. Theprocess is called cementation,and is carried on by packing the bars of iron in brick-work boxes, with a mixture of salt and soot, or with char-
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Keywords: ., bookcentury1800, bookdecade189, booksubjectscientificrecreations
