An apparatus to produce a blast of air. The blacksmith's bellows is one of the earliest forms of these. Various machine-blowers are now in use, which give a very powerful blast, some of them being rotary machines, others utilizing the steam jet to produce a blast. Another form of blower is the electric fan, with rotating vanes, used to keep the air in motion in stores or offices. Powerful fans are used for the melting of iron in cupolas, and air blasts are turned into smoke-stacks to make a powerful draft for locomotives, steam fire-engines, etc.