42 
REACTIVE LOCOMOTION. 
their own forming f ” Very nearly, Mr. Pettigrew, very 
nearly, but not quite ! In the children’s play of <c hide 
and feek,” even “ burning ” is not always “ finding.” 
No bird-principle of locomotion in the air can explain 
the wonderful movements of the dragon-fly. Where the 
denfity of the fluid is fuch as to furnifh the creature with 
a fulcrum almoft or quite complete in itfelf, as in the cafe 
of water and the darting through it of fpeckled trout, 
locomotion refulting from direct action can be underftood 
and admitted; but where, as the preliminary to a loco¬ 
motion that depends upon a confant and continuous 
creation of force-denfity, flying creatures exhibit the dart¬ 
ing movements of the dragon-fly and the floating move¬ 
ments of the bee, and over and above all the ftanding-ftill- 
in-the-air performance of the fly, nothing fhort of the 
indirect locomotion refulting from fuperinduced wind- 
preflures feems to be fuflicient to account for them. All 
the flying machines ever made by man have failed, and 
thefe have all been direCt action or propelling machines. 
Why not now try the oppofite (do it the other way), and 
fee what can be accomplifhed by confining the whole of 
the power and all the fanning action of the machine to 
the work of communicating force to the air f When this 
machine fails, fhould fuch be the cafe, we fiiall have then, 
I fear, exhaufted the mechanical methods of getting 
through the air, and will be compelled to await further 
developments in electrical fcience. Nearly forty years ago 
