Sir Charles Parsons 179 



mentioned, the first Parsons steam turbine was used to 

 drive an electric generator in Cambridge. To-day almost 

 every electric power plant in the world (save those worked 

 by water power) is driven by steam turbines. The tre- 

 mendous speed of the steam turbine, which was at first 

 a disadvantage in the driving of screw propellers, is of 

 great value in electrical works, where the speed of direct 

 drive is ten to fifteen times greater than was possible with 

 the older type of reciprocating engines. 



The speed is, indeed, so great that centrifugal force 

 becomes about twelve thousand times as great as gravity ; 

 in other words, every pound weight has an outward pres- 

 sure of five and a half tons. How to counteract such 

 tremendous forces was one of the difficult problems which 

 had to be solved by Parsons when he began to install these 

 plants. 



Soon after the Cambridge installation orders began to 

 come in for turbine-driven lighting-plants for ships. The 

 first Atlantic liner to be lighted with electricity was the 

 City of Berlin, in the year 1888. This experiment was 

 quite successful, and soon all other lines followed the 

 example. 



Turbines are also used for blowing-engines in smelting 

 works. These are simply bellows on a great scale. They 

 take up very little room and are very economical. There 

 is little wear and tear, and very small cost for oil and 

 maintenance. The power is so great that a furnace can 

 easily be blown free if it happens to choke. In one works 

 two small turbo-exhausters took the gas from two hundred 

 and sixty tons of pig iron per day, whereas before they 

 were installed five large exhausting-machines were unable 

 to deal with more than one hundred and sixty tons. 



The steam turbine has another use — in rolling-mills. In 

 one Scottish mill designed for rolling steel plates for ships 

 a Parsons turbine was installed with a nominal output of 

 seven hundred and fifty horse-power. But it was found 



