In the course of time cast-iron was substituted for wood, and the iron blast- cylinder, one of the forms of blowing engines still in general use, was obtained.
In this way was evolved the box-blower, with single-acting movement of a piston.  In the course of time cast-iron was substituted for wood, and the iron blast- cylinder, one of the forms of blowing engines still in general use, was obtained.  In addition to this, for low pressures and large volumes of blast, fans and blowers are largely used.