REACTIVE LOCOMOTION. 
27 
air by the force of the winds. Birds with no wing move¬ 
ments are impelled through the air as weighted and 
balanced inclined planes operated upon by combined wind 
forces, the impullion producing pajfive locomotion. Birds 
hover or Band Bill in the air under the combined 
operation of winds and wings. And birds mount into the 
air and urge themfelves forward under the adion of their 
wings in their dual capacity of fan-blowers and propellers. 
Bats and large-winged light-weight creatures are animated 
parachutes. But the 
InfeSi world , reprefented by the Dragon-fly , 
have an aerial locomotion of their own, bafed on relatively 
fmall wings driven at high velocities on the principle of 
the fan-blower, their movements through the air not 
being the readive dired locomotion that refults from the 
play of wings when employed in their combined dual 
capacity of fan-blowers and propellers, but the readive 
indirect or pajfive locomotion refulting from the employ¬ 
ment of wings in their fingle capacity of fan-blowers. 
This fpecies of infed locomotion is analogous to the paf- 
live locomotion I have mentioned where the bird is im¬ 
pelled by the adion of combined wind-forces direded 
againft the balanced body of the creature as a weighted 
inclined plane; the difference being that in the cafe of 
the infed the wirid-force and preffures originate in the 
infed, but in the cafe of the bird the wind force and 
