CHAPTER VIII 



TRANSPORTATION IN THE AIR 



176. Early dreams of flying. " The way of a bird in the air '' 

 was even for Solomon an object of envious contemplation. The 

 bold endeavor of Daedalus, though quickly disastrous, the flight 

 and speed of Pegasus and the Magic Carpet, the flying machine 

 of Darius Green, and the far-reaching fancies of Jules Verne 

 were anticipations of what has to-day become a reality that is 

 still rich in unfulfilled possibilities. It is to-day comparatively 

 simple to rival in speed the flight of a bird ; and transporta- 

 tion through the air is now fully within the range of the 

 practicable. 



177. Types of aircraft. Men have made the air a medium 

 of travel and transportation by two different types of aircraft. 

 One type is represented 



by the balloon, which is 

 lighter than air, volume 

 for volume. It is lifted 

 by the buoyant force of 

 the air in the same 

 fashion as water buoys 

 up bodies. The other 

 type is the heavier than 

 air machine, the air- 

 plane (Fig. 138), which is sustained as it moves by the pressure 

 of the air on the lower surfaces of its planes. The airplane is 

 lifted as the bow of a boat when moving rapidly, and as the 

 hydroplane rises when it is driven forward. 



389 



FIG. 138. A biplane. 



