THE THEORY OF THE KITE 133 



against the strip, and weight it until there is a definite pull, 

 when the balance is drawn along with a uniform motion. 



b. What is the pull when the balance is drawn lengthwise 

 of the board ? This is the total force which is necessary to 

 move the block with its load of weights. Now draw the 

 balance a little toward the strip so that the string crosses the 

 protractor at an angle of 5 from the line of the block's mo- 

 tion. What pull is necessary? What has happened to the 

 extra force? Increase the size of the angle, and note the 

 increasing loss of force. A pull, or a push, at an angle to 

 the desired direction of motion, has a component of loss. 



98. THE THEORY OF THE KITE 



With the kite it is necessary to resolve the force of the wind, 

 which blows for the most part parallel with the earth's surface, 

 into two forces. One must act at right angles to the surface 

 of the kite, as the effective force, and the other parallel to the 

 surface of the kite, though not affecting the latter. The per- 

 pendicular force must then be resolved into two forces, one 

 acting parallel to the string, producing the " pull " of the kite, 

 and the other acting at right angles to the string, producing 

 the lifting of the kite itself. By regulating the angle at which 

 the string leaves the kite, the latter may be made a " puller " 

 or a " high flyer." The more the top of the kite is inclined 

 toward the string, the higher the kite will fly until the limit of 

 height for that kite is reached. 



Kites may be balanced by means of a tail or by so shaping 

 the surface of the kite that it sheds the wind equally from the 

 two sides. The Malays have evolved this style, and it is the 

 best for simple construction. The box kite, which consists 

 of two or more cells into which the wind blows, is more com- 



