190 Master Minds of Modern Science 



having eight wheels, connected with a central pivot, 

 which rotate in a circular bed. It is like a roundabout 

 without a top. If you invent a new surface for roads 

 which you believe will wear longer than any other, take 

 it to Teddington. There they will lay a strip of your 

 material on the circular track and set the eight wheels 

 in motion. For seven hours a day, week after week, 

 the wheels will travel over that prepared track, until the 

 scientists know just how long the surface will stand the 

 * traffic/ and can compare the result with the carefully 

 compiled statistics relative to other road materials. 



One more instrument in this department of wonders 

 must be mentioned. It is a little machine so sensitive to 

 earth tremors that it will record the passage of traffic 

 several hundreds of yards away. This will be used for 

 making observations of the actual blow that a wheel 

 delivers to the road; the testing-ground will be an 

 artificially prepared rut. 



Apart from the Tank, however, perhaps the most 

 interesting feature of the Laboratory is the Aerodynamics 

 Department, where are to be found the wind tunnels. 

 These are fearsome to the eye. Imagine a huge wooden 

 funnel, fourteen feet broad and seven feet high, supported 

 on steel legs, with a mighty propeller at one end which at 

 a maximum speed can suck air through the funnel at one 

 hundred feet per second, which means that twenty tons 

 of air pass through the tunnel every minute. A man 

 would be swept off his feet by such a blast. Even an 

 aeroplane would find it difficult to face the storm — and 

 that is just why these wind tunnels were built. For 

 they are the airman's friend, and with their help the 

 scientist has collected much valuable information about 

 the pressure of wind and air on aeroplane wings and 

 fuselages. Otherwise this could only have been collected 

 slowly, and through infinite risk of life and limb in the 

 air itself. 



