TETRAHEDEAL KITES. 



143 



shattered to pieces, but beyond a few broken sticks it was as well and 

 strong at the end of the journey as when it started. 



The big tetrahedral kites, twelve feet and more on a side, look like 

 awkward things to travel with or to store away, but they may be 

 packed as handily and in as small compass as blankets or rugs. Each 

 kite is made in collapsible sections, which open and then fold up, as 

 shown in Fig. 12. Half a dozen large kites can in this way be carried 

 in a trunk from place to place and put together in a few minutes. 



The more recent experiments made have been to obtain a giant 

 manlifting kite, or flying machine, that will rise from the surface of 

 a lake. Any one who has ever watched a heavy bird rise from the 

 ground has doubtless noticed that 

 it runs along the ground for a 

 few feet before it rises — the bird 

 must acquire some momentum 

 before its wings can lift its heavy 

 body into the air. The natives of 

 certain parts of the Andes under- 

 stand this fact very well and hy 

 means of it catch the great 

 Andean vultures. A small space 

 is shut in with a high fence and 

 left open at the top. Then a 

 lamb or piece of carrion is placed 

 on the ground inside. Presently 

 a vulture sees the bait and swoops 

 down upon it ; but when once 

 he has lighted on the ground 

 inside he can not get out for 

 he has no running space in 

 which to acquire the momentinn 

 that is necessary before his wings 

 can lift him. In the same way 

 the first difficulty of all flying 

 machines is to acquire the first 

 momentum that will lift the machine into the air. To over- 

 come this difficulty the flying machine inventor usually shoots his 

 machine from a high platform which makes it necessary for the ma- 

 chine to rise immediately. But if the flying machine can not start 

 in a natural way the chances are its method of working is not right and 

 it is doomed to failure. And even if a machine could fly perfectly 

 after it had been started how could it get up again if it came down for 

 food or fuel at some point where there was no platform and starting 



Fig. 12. A Section of a Kite folded up 

 FOR Packing. 



