BOOMERANGS. 



them the boomerang has to spin in the direction 

 of the arrows G and H. The spin is further 

 assisted by a final push of the fingers in the 

 direction of the arrow G. The spin due to 

 the presence of the fingers as an obstacle at 

 D is additional to, and intensifies, the spin 

 which the boomerang, like all sticks thrown 

 from one end, acquires from the swing given 

 to it in the act of throwing. 



FiQ 14. VERTICAL DEFLECTION OF BOOMERANG'S LINE 

 OF FLIGHT. 



The steady flight of the boomerang being 

 accounted for by the gyroscopic action of the 

 spin given to it at the moment of throwing, 

 there remain to be considered some of the pecu- 

 liarities of flight which have earned for it its 

 special reputation. 



First, then, the boomerang can return to 

 the thrower. 



Let A B (Fig. 14) represent the thrower, 

 and the dotted line A C the direction in which 

 the boomerang is thrown. Now, if A C were 

 a plane surface of polished and lubricated 



53 



