-84 OUR PHYSICAL WORLD 



or to bring it to rest. The inertia of the tail tends to restrain 

 the kite and keep it from bobbing about erratically. 



When a kite is built of several plane surfaces set at varying 

 angles to each other as in the box kite or the tetrahedral kite 

 (p. 83), or presents curved surfaces to the wind as in the bow kite 

 or bird kite, the gusts of wind strike these at such varying angles 

 that the kite is impelled in a dozen different directions simul- 

 taneously, with the result that these various impulses work 

 against each other, and so the kite remains quite steady in the 

 main air current. Such kites, therefore, fly well without a tail. 



Kite-flying may be made to afford a great deal of amusement 

 and incidentally much experience with winds that gives the pupil 

 a real appreciation of their power and a first-hand acquaintance 

 with some of the problems involved in their utilization for man's 

 purposes. Indeed, it is a sport followed in many countries by 

 adults. It requires considerable skill to fly your kite higher 

 than any of your competitors. Tandem teams of box kites 

 will fly to great heights. Send up a box kite Jetting out 200 feet 

 of string, then fly another one on 50 feet of string and fasten the 

 free end of the string to the string of the first kite. Let out more 

 string and fasten on another. 



You may slip colored paper windmills or disks of paper on to 

 the string of your kite, passing the latter through the hole at the 

 center of the disk or windmill and so let them go sailing or 

 twirling up to the kite. You may draw a face on your kite or the 

 head of an animal. A kite that is covered with black paper on 

 which are pasted tissue-paper circles for the whites of the eyes, 

 red tissue-paper nostrils and lips with white paper teeth is a 

 conspicuous and comical object in the air as it goes bobbing 

 about. 



We boys used to fasten a sharp, narrow strip of tin on to the 

 kite string, then try to cut the other fellow's kite string, and so 

 see who could keep his kite up longest without accident. I 

 remember, too, our ambitious plan of building a great, big kite. 

 It was of the ordinary type but extraordinarily large -15 feet 



