POPULAR SCIENCE REVIEW. 
FLYINa MACHINES. 
By FRED. W. BREAREY. 
Honokart Secretary to the Aeronautical Society of Great Britain. 
I N its normal state, the air is inapplicable as a power, but it is 
capable of becoming an overwhelming power, either by 
natural or artificial causes, as in the whirlwind and tornado or 
by rushing forcibly through it, as would be exemplified were 
the sails of a windmill rotated rapidly against it. 
Thus the bird may create for itself in a calm, by the agitation 
of its wing-surface, the power w’hich supports and prolongs its 
flight in a horizontal or ascending line ; but is also capable, in 
the calm of a sultry summer’s day, by the mere momentum of 
its own weight, of gliding for an immense distance upon an un- 
yielding plane, thus converting the inert air into a fulcrum or 
support. 
In- such a case, two only of the three requisites for successful 
flight are brought into action, viz. surface and weight, the third, 
force, being held in reserve for extraordinary occasions. 
This gliding motion, the writer has observed in a parachute 
which detached upon one occasion at no great height above 
his head on a calm evening sailed away down a gradually in- 
clined plane. 
It is upon bodies like these possessing extended surface, and 
brought under the influence of gravitation, that experiments are 
required. 
There can be no question in dispute, as to the possibility of 
so manipulating and inclining the surface or portions of the 
surface of a similarly descending bodjq so as to prolong the 
gliding motion, and convert it into one obedient in some 
degree to the will of the operator. When the two antagonistic 
