Although the turbine principle of utilizing the heat energy in steam and converting it into useful work has been. Experimented upon for many years, it is only since the inauguration of the twentieth century that steam tur bines have been brought to the front. As efficient power producers. The piston of the reciprocating engine is driven back and forth by the static expansive force of the steam, while in the steam turbine not only the expansive force is made to do work, but a still more important element is utilized, viz., the kinetic energy, or heat energy latent in the steam, and which manifests itself in the rapid vibratory motion of the particles of steam expanding from a high, to a low pressure, and this motion the steam turbine transforms into work.