36 
REACTIVE LOCOMOTION. 
naturally like a rotary pump, and works centrifugally 
within a box: the conffrudtion producing fridtion, wafte 
of power, and coft. 
Now turn from this pidture and look at the little live 
blowers made by the Creator. As I have already faid, 
bees ventilate their hives by the adtion of their wings, a 
number of bees being for this work ftationed in the paf- 
fages and at the entrances to the hives : thofe at the door¬ 
ways holding faff by their feet, to prevent being blown 
away by the wind-blafts of their own wings. 
Now here we have before our eyes the example of 
natural fan-blowers, without boxing, not working centri¬ 
fugally, producing perfedt blafts of wind in the open air, 
to which they can give any diredtion they choofe ! What 
machine of this fort has man ever conftrudted comparable 
to this ? The moil remarkable thing that happened in 
the courfe of my obfervations, was when I difcovered that 
wings flapped at right angles to the body of the creature 
produced an air-blaft, the whole of which was diredted 
backwards ! This mechanical puzzle I one day had the 
opportunity of finding out for myfelf. A large moth or 
miller, about the fize of a bumble bee, finding itfelf in my 
room, and unable to get out, naturally took to where the 
light was ftrongeft—the window; but the window was 
clofed; and my attention was attradled by the frantic 
efforts made by the creature in its attempts to force a 
paffage by butting its head violently againft the pane. 
