396 
POPULAR SCIENCE REVIEW. 
will ever be able to navigate the air ? First, of course, the fact 
that creatures possessing weight are endowed not only with perfect 
adaptation of means, but with the mechanical instinct to put 
them to use without waste. The students of aeronautics say 
that they can imitate such means. It is clear, however, that to 
construct the required apparatus, without the attainment of 
precise knowledge as to the work which the apparatus is to per- 
form, would be useless labour. Societies have been formed to 
discuss the mechanical conditions. The Aeronautical Society 
of Great Britain, of which I have the honour to be honorary secre- 
tary, was formed immediately after the subject was introduced 
by me in a paper read before the British Association at Bir- 
mingham in 1865. The papers and discussions, printed in our 
annual reports, have thrown much light upon the action of a 
bird’s vibrating wing upon the air. 
We all know what this thin medium can effect when in 
motion as what we call wind. Our critics, courteously some- 
times, strive to conceal their amusement when we talk to them 
of one day navigating the air. To them the balloon, being a 
fact accomplished, presents the only means because of its 
buoyancy To them the tornado presents no suggestion. 
Ships, trees, houses, and towns may be scattered like sand, but 
to them no idea is presented. I lately read a report of a hurri- 
cane in New South Wales in which the speed and force of the 
air were carefully taken. For a short time the velocity of the 
wind was stated to be 153 miles per hour, and the pressure no 
less than 117 lbs. upon a square foot of surface exposed to it. 
When speaking to men of science upon the subject of the 
navigation of the air one often hears the expression : 44 Yes ; I 
don’t doubt that some day or other the question will be solved, 
but not in our day.” This is meant to be an easy and safe way 
of avoiding the discussion of the subject. The savant smiles, 
and says, 44 Good day to you ; ” and leaves his interlocutor in 
wonderment that even with his hands well sanded his eel has 
escaped him. 44 Not in our day,” he repeats, and ponders in 
wonder as to the true application of the expression by so very 
learned a man. 44 Not in our day ; ” and why not in our day ? 
Has there ever been in the world’s history a time so marked by 
various discoveries and inventions as the present day ? 
The wonderful grasp which man has obtained of force, of the 
origin of which he is ignorant and of which he yet makes ex- 
cellent use for many purposes which were utterly inconceivable 
a few months or years since, absolutely throws into insignifi- 
cance the hopes of those who desire, by mechanical means alone, 
to apply to the air the same conditions imparted to it by the 
mechanical wing-action of the bird, by which it sustains in 
motion a weight out of all proportion, in human conception, 
