New Developments in Science 601 



On some railroads, tne passenger cars on through trains are 

 air-conditioned. Thus the discomfort of summer travel by train 

 is largely eliminated and winter travel is also improved. 



It is believed that air conditioning, together with improve- 

 ments in health conditions brought about by proper sanitation and 

 the control of disease-bearing insects, will eventually open up the 

 tropics to a much greater development by white men than has 

 heretofore been possible. Large electric companies of this country 

 have sent investigators to the tropics to make a survey of these 

 possibilities. 



The Gyroscope. A scientist with a sense of humor once 

 packed his suitcase to go on a trip. In it he put a strange device 

 consisting of a heavy metal wheel mounted in a metal framework. 

 When he reached the station he opened the suitcase, set the wheel 

 spinning rapidly, then closed the suitcase again and called a 

 porter. The porter picked up the suitcase and started to carry it 

 to the train. All went well until he tried to turn a corner, when 

 the suitcase began to act very strangely. No matter how hard he 

 pulled and tugged, the porter simply could not make that suitcase 

 turn the corner. It resisted all his efforts until at last the scientist 

 came up and stopped the wheel. The porter thought the suitcase 

 was bewitched, but the scientist knew that its strange actions 

 were due to the spinning wheel, or gyroscope, which he had 

 placed inside. 



Have you ever had a toy gyroscope? If you have, you can 

 easily see why this strangely-acting device has contributed so 

 much to the advancement of mechanics in the last few years. 

 The gyroscope is essentially a heavy wheel, mounted in a metal 

 frame. When this wheel is revolving rapidly, its inertia 1 tends to 

 make it remain in the same position. A spinning top has this 

 same characteristic. In fact, a top is in effect an unmounted 

 gyroscope. When a top is spinning rapidly, it is difficult to knock 

 it over. If you try to push it over, it merely moves along in the 

 same upright position. Even if you knock it from the table to the 

 floor, it continues to spin in the same position it had while on the 

 table. It is the same way with the gyroscope, except that the gyro- 



1 See description on page 15. 



