398 
POPULAR SCIENCE REVIEW. 
The great difficulty which the inventor has met with in 
his desire to encounter the atmosphere in the manner of a bird 
has faced him at the very first step ; it is, we may say, the goose 
step, the first step in flight — flight itself by simple wing 
action. We have, however, latterly attained to this, and have 
thereby assured ourselves that those natural flying machines — 
the birds — are not supported and propelled by some occult 
agency unrecognized in any school of science. 
That no highly rarefied air in or about the body of the bird 
is essential to flight. 
That no arrangement of feathers so that in the upward stroke 
the air shall pass through them, whilst in the reverse stroke 
they shall be impervious to its passage, is necessary to accom- 
plish an imitation of flight. I have shown many examples. 
When, however, we come to the transport of weight by such 
artificial means — such weight, for instance, as is presented by the 
living prototypes whose shape and proportion of wing we 
attempt to imitate, such as the rook, the blackbird, swallow, or 
albatross, with twelve feet stretch of wing — we become perplexed, 
or, rather, we have hitherto been perplexed, because it is the 
object of this paper to show that this difficulty is receding 
before the more perfect knowledge which is always attainable 
by those bulldogs of science who are determined to retain 
their grip of an object of which they have once realized the 
flavour. 
Experiments with the wings of the dead bird have hitherto 
been unsatisfactory. 
I have myself not been successful in attaining flight by the 
attachment to m}^ apparatus of any birds’ natural wings. I 
attribute this to the absence of that elasticity which per- 
tains to the living prototype. The best examples of flight 
by models, which I have yet attained, are in those instances 
where the wings have been made more than usually flexible. 
This is an encouraging feature, because the manufacture of a 
rigid wing of the dimensions necessary to support a man would 
necessitate great weight ; in fact, it would be impossible to con- 
trol its action by any motive power without great danger of 
fracture. I have seen such a wing fractured at the first stroke. 
The apparently insuperable difficulties attending the accom- 
plishment of manual flight by wing action have stimulated 
efforts in the direction of plane surfaces propelled by screws. 
The late Sir Greorge Cayley, a Yorkshire baronet, well known 
for his persistent experiments for the attainment of locomotion 
in the air, states, with respect to plane surfaces, “ About sixty 
years ago, many experiments on a large scale were made by this 
means, some of the aerial vehicles having three or four hundred 
feet of canvas extended on masts, and braced by rigging, and 
