Reproduced by permission of the Cunard Co. 



THE ROTOR OF A PARSONS STEAM TURBINE 



The steam turbine has replaced the reciprocating or piston steam-engine in electrical power-houses, as it can be connected directly 

 to the generators and driven at very high speed without vibration. This illustration shows a turbine with the upper half of the 

 casing removed, leaving the rotor or revolving part exposed. A huge number of blades project in rows from the rotor, like the bristles 

 of a circular brush. These alternate with rows of similar fixed blades projecting inwards from the casing. As the steam passes from 

 one end of the casing to the other, through the space between casing and rotor, it is repeatedly directed on to the moving blades, 

 and its pressure imparts rapid rotation to the rotor. 



ELECTRIC INCANDESCENT LAMPS 



The electric incandescent lamp contains a metal wire, the ends 

 of which are led out to exterior plates in the top so that they may 

 be connected with the lighting circuit. Electric current en- 

 deavouring to pass through the wire meets with great resistance, 

 which causes the filament to become white-hot and intensely 

 luminous. 



The lamp on the left has a very long, thin wire wound up and 

 down over wire spiders projecting from a central glass stem. The 

 bulb is exhausted of air through the tip before being sealed, and 

 the absence of air prevents the wire being burned up. The 

 lamp on the right has a much shorter wire forming part of a circle; 

 the bulb in this case contains some gas which has no effect on the 

 filament. The "gas-filled" is considerably mors efficient than 

 the other type ; and in its larger sizes is now much used instead of 

 arc lamps for street lighting. 



By permission oj the British Thomson-Houston Co., Ltd. 



