AERIAL LOCOMOTION 425 



faces either large or small, although the lifting-power is less 

 than when horizontal surfaces are employed, because the factor 

 of safety is greater. One of the chief causes that have led to 

 disasters in the past has been lack of stability in the air. Auto- 

 matic stability under varying conditions is surely of the very 

 first consequence to safety, for what would it profit a man were 

 he to gain the whole world and lose his own equilibrium in the 

 air? A kite composed exclusively of multitudinous winged-cells 

 seems to possess this property of automatic stability in a very 

 marked degree. If then its lifting-power is sufficient for our 

 purpose there is no necessity for the introduction of a factor of 

 danger by the addition of horizontal surfaces. Of course the 

 addition of such surfaces would enable us to secure the desired 

 lifting-power with a smaller and therefore lighter structure, and 

 this would be of advantage if we could be sure of its stability in 

 the air. 



In employing tetrahedral winged-cells alone, upon the hollow 

 plane of construction in which large empty spaces occurred 

 within the kite, a practical difficulty was encountered arising 

 from the enormous size of the structure required for the support 

 of a man, combined with the increasing weakness of the struc- 

 ture as it increased in size. The discovery that the cells may 

 be closely massed together without marked injurious effects has 

 completely remedied this difficulty ; for upon this plan, not only 

 is the structural strength improved by an increase of size, but 

 the lifting-power increases with the cube of the dimensions, so 

 that a very slight increase in the dimensions of a large kite in- 

 creases very greatly its lifting-power. We now have the possi- 

 bility of building structures composed exclusively of tetrahedral 

 winged-cells that will support a man and an engine in a breeze 

 of moderate velocity, without the necessity of constructing a 

 kite of immoderate size. The experiments with the " Frost 

 King" made in December, 1905, satisfied me upon this point, 

 and brought to a close my experiments with kites. 



Conclusion. 

 Since December, 1905, my attention has been directed to other 

 points necessary to be considered before an aerodrome of the 



