The Developing of Power 



power of the world was derived from muscular force, now 

 more than ninety-two per cent, of the utilized power of the 

 world is obtained by artificial means. 



When the power of steam began to supplant the power 

 of muscular force, the necessity arose for a method of meas- 

 uring this new power. It was at first measured in units of 

 human muscular strength, the power of ten men being equal 

 to that of one horse. The system of measuring power was 

 then changed and the force that could be exerted by a heavy 

 horse during a given period of time was then adopted as a 

 standard of measurement and since that time the power of 

 all steam boilers has been measured in horsepower. A 

 horsepower, therefore, means the strength or force required 

 to lift an object weighing 330 pounds to a height of 100 feet 

 in one minute, or 33,000 pounds one foot in one minute. As 

 an illustration of the increase in concentrated mechanical 

 power the mind of man has conceived and his hands con- 

 structed a single machine in the form of a steam turbine that 

 furnished power equal to that of 2,000,000 men. 



After a method for the practical control of the power 

 of steam was discovered, the next problem that had to be 

 solved was a method of transmitting the power generated 

 by the parent motor to the machines that were to do the 

 work. In nearly all cases where steam is used for power, it 

 is necessary to transmit this power for considerable dis- 

 tances to the machines which are employed to do the 

 required work. Many methods have been devised in accom- 

 plishing the transmission of power and these methods are 

 classed as gears or gearing, belts, chains, ropes, compressed 

 air, hydraulic pressure, and electricity. For short distances, 



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