New Developments in Science 605 



the frame of the gyroscope indicates the points of the compass. 

 This dial differs from the magnetic compass in having no needle. 

 Instead, the whole dial, by remaining always in the same position, 

 regardless of which direction the ship turns, indicates the dif- 

 ferent points of the compass. 



Other Uses of the Gyroscope. Many other uses of the 

 gyroscope have been developed. In both ships and airplanes, gyro- 

 scopes are used in automatic control instruments called "auto- 

 matic pilots." On ships the gyro-pilot is sometimes used. This 

 device is connected with the gyro-compass, which sets up an elec- 

 trical connection with the steering apparatus whenever the ship 

 starts to move from the course set. Thus this tireless mechanical 

 pilot works day and night without rest and with far greater 

 accuracy than any human helmsman. In the airplane, the auto- 

 matic pilot works similarly. The gyroscope makes electrical con- 

 nections which operate the airplane's controls. 



One of the most interesting applications of the gyroscope is 

 the automatic railroad track recorder, which consists of a gyro- 

 scope and a complicated system of machinery that registers any 

 tendency to change the position of the gyroscope. This ingenious 

 device thus detects the slightest inequalities of the track as the 

 train in which it is carried passes over the rails. Any difference 

 of elevation of the two rails, any undue depression, or any rail 

 spread is not only detected, but automatically recorded on a chart. 

 The automatic track recorder, when placed on a train and run 

 over a stretch of track, does the work of many track-walkers in 

 far less time. The figures it records are used as a basis for future 

 track repairing. 



Streamlining. Ever since men first began to build boats, 

 they have been faced with the problem of cutting down the 

 resistance of the water so that the boats would move forward 

 more quickly and easily. For thousands of years it was believed 

 that a long, slim shape, sharp at the front, gave the best speed. 

 Until recent years, therefore, the fastest boats have been built 

 with long, sharp bows. Since air offers resistance much like that 

 of water, racing automobiles and dirigible balloons were also built 

 with pointed fronts. 



