REACTIVE LOCOMOTION. 
29 
the latter enabling the wings to convert large trails of 
air into fupporting areas. It is alfo accounted for by the 
multiplicity of the movements of natural wings, thefe 
enabling the pinions to create and rife upo?2 currents of 
their own fortning , and to avoid natural currents when 
not adapted for propelling or fuftaining purpofes. (See 
Pettigrew’s “Animal Locomotion,” pp. 218, 219.) 
The words I have italicifed, ££ to create and rife upon 
currents of their own forming,” exprefs really the gift of 
the problem to be folved, and yet Pettigrew himfelf 
evidently failed to perceive it, or he would not have 
elaborated fo extenfively his u figure of 8 ” theory, 
and neither would he have condemned Profefior Marey 
and Borelli as he has done. Nothing is more common in 
invention than for a man to have a difcovery in his hands 
and not know how to ufe it, and the difference between 
the machine that fucceeds and the one that don’t, is fo 
exceedingly fine oftentimes that the unfuccefsful inventor 
feels himfelf aggrieved by the fuccefs of the other whofe 
machine he confiders to be ££ exadly like ” his own, and 
yet his own won’t work and the other will. But the world 
judges by refults . 
The miftake of mankind has been in trying to fly. If 
the fimple theory that I fhall endeavour to fet forth in the 
following pages fhould prove to be the corred one, then 
the world has been fooling itfelf for ages with wing move¬ 
ments—“ wave” theories, ££ rowing motions of the wings,” 
