HYDRO-ELECTRIC POWER STATIONS 



CHAPTER I 



GENERAL INTRODUCTION 

 HISTORY OF WATER POWER AND ELECTRICAL DEVELOPMENTS 



THE use of water power for industrial purposes dates back to 

 very ancient times. The crude current wheels were familiar 

 to the Chinese on the Yellow River and the Hamites on the Nile 

 and Euphrates fully three thousand years ago. These wheels 

 operated entirely by the kinetic energy of the moving water, and 

 the power thus obtained was utilized for raising the water of the 

 rivers for irrigating the arid land and also for grinding of corn 

 and other simple applications. Similar current wheels, although 

 necessarily of improved design, have been most widely utilized 

 and, while very inefficient, they are still used for minor irrigation 

 and other purposes in many countries. 



The first radical change in the art was the use of channels, 

 by which the water could be conducted and directly applied to 

 undershot wheels. This improvement resulted in the utilization 

 of some 30 per cent of the theoretical water power, and the system 

 maintained its prominence until almost the middle of the eigh- 

 teenth century, when the overshot wheel was invented by John 

 Smeaton, who showed that if the bucket wheel was changed into 

 an overshot form, its useful efficiency would be increased to over 

 6Q per cent. In this type of wheel the energy of the water was 

 applied directly through its weight by the action of gravity and 

 yielded a very high efficiency. Overshot wheels were formerly 

 built of great size. One at Laxey, Isle of Man, constructed about 

 1865 and is said to be still in operation, is 72 feet 6 inches in 

 diameter and develops 150 horse-power. A number of overshot 



