ABSTRACT
As hydraulic energy is represented by the product of discharge and pressure head, a complementary availability of river flow and potential head is a necessary prerequisite for hydro-electric power to be an eco nomic proposition. Unfortunately, topographical conditions in England are relatively unfavourable, but in the mountainous terrain of Scotland and in many countries abroad the exploitation of the water resources has proved to be fully justified. Some idea of the importance of water power may be gained from the fact that at the present time it contributes about one quarter of the total world production of electricity.
