[1714]. Arms and boss cast in one: the rim in segments, bolted together and to the arms.

[1715]. Tension wheel. The tie spokes are sometimes arranged in two sets at a slight angle to each other to prevent the rim turning without the boss. Bicycle wheels are of this class.

[1716]. Wrought-iron wheel, with cast boss.

[1717]. Wrought-iron wheel, with cast boss.

[1718]. Rim in segments bolted together, wood arms and cast boss, with sockets to receive arms; this type is much used for water wheels.

[Larger plate.]

[1719]. Railway wheel: boss of cast iron with wrought-iron arms cast in. The rim is of rolled iron or steel riveted on. There are numerous methods of fastening the tyres to arms, detailed in the Engineer, July 23rd, 1880.

[1720]. Spring rim split pulley.

[1721]. Segment fly-wheel, with long radial bolts to secure the rim, arms, and boss together.