Evening star. [volume] (Washington, D.C.) 1854-1972, 1892-02-06

more than the pigeons wing. This would
seem to be very easy problem, yet am GER
tain to strike difficulties in the way of the suc-
cessful photography Of insecta For example.
the flight Of insects is very erratic and there is
no means Of controlling it. The actual
speed Of the body through the air is also
comparatively slow, and so the cameras
must be arranged very close together
and the successive exposures made with
extreme rapidity so as to get complete
series Of motions have estimated that il will
be possible for me to obtain an exposure Of not
more than one-twenty-thousandth part Of a
second, vet do not think that shall need so
high a rate. am aided in this by the reduc-
ton of the size of the lens, which, being but an
inch in diameter, can be covered and I'M
covered much more quickly than one Of three
inches.
Il have made arrangements for the building
Of new instrument suited to this more micro
scopic work that have projected. and hope
to have it completed in time to begin with it
next summer. l shall depend altogether upon
electricity to produce a very high rate Of mo-
ton, that shall then be applied TO the shutters
by means of making aud breaking the cur
rent
Now, the problem is to get as accurate a
photograph Of the wing Of an insect as have
OF the foot of a horse. 1 hope to be able to get
an impression on my plate of at least eighth
OF an inch In the case of the common house fly.
and perhaps of half an inch. This will, OF
course, be enlarged for the purposes of anal
ysis and study. This process may be accom-
Ihn 6y means OF photography, Projectins
the image upon q plate through a lens, OF II
may De done by an artist, drawing with such a
prolectlon on a screen as a model. have nc
doubt that shall be able to obtain sufficien,
detail Tor as much enlargement az may be
necessary.
HOW A BIRD FLEE
II was, perhaps, the first to demonstrate be-
yond doubt that bird in flying moves the
wings not only in the direction that we discern
with our naked eyes, but in an independentman
ner, by turning the primary feathers edgewayi
to the air, and SO reducing the friction. Thi.
had been theorized upon by Scotch zoologist
Prof. Jeffries, but he had no facts at his dis
posal. When L sent out my results | heard
from him to the effect that he had already
formed a theory in this direction. My first at
tentlon was called to the mater through {
peculiarly which l noticed in some of my
photographs of birds, for which could not &C.
count, except upon the theory that the bird
had voluntary control of the individual
feathers of the wing that aided il
in its fight. I thereupon had the demon
strator OF comparative anatomy at the Uni
versity of Pennsylvania d;ssect bird: and We
found that it was provided with a system Of
tendons that gave to ii a voluntary control over
each primary feather of the wings. When We
pulled these cords the feathers described 9
quarter of a revolution, and gave to the wing q
lattice-work appearance, and enabled it e
move through the air with the least possible
amount of friction. We also found the bird
does not move these feathers in this way when
ever 1t flaps the wings. unless II SO wlshes-thai
Is, the two actions are entirely independent.
This gave us an important result for Use in
the experiments in the line of aerial navigation
l am now convinced that the bird-wing theor,
Is not the correct one, and that in the flight Of
insects We shall find much simpler and there
fore more practicable method, that NAV affort
a reasonable basis for success. l have com
municated with all of the leading scientist,
who are now engaged in the study OF this prob
lem, and they agree with me that there is vet
vast field left unexplored.
The question is whether or not the insect
wing makes the return of the flap without any
independent motion. 1t seems 10 be a matter
OF the plane adopted. and yet there is nothing
to prove that there is not sort OF hinge in the
center OF the wing that folds and thus pro
duces the same result as is obtained by the
bird turning OF Its feathers. At ali events the
motion must be much simpler and therefore
better adapted to the uses of man. l am no
promising anything nor do l predict, but
think that there may come from this series o.
experiments some useful information for the
students of the flying machine.
Il have communicated with all of the prin
cipal workers in the problem-Edison. Lang
ley, Sir William thompson, Sir John LubLoci
and Prof. Ray Lancaster. Mr.. Edison Is heart
lily IN accord with my views and have an as
surance OF his belief in the practical nature o
my plan In recent letter, In which he saw
that competent investigation of the move
ments of the wings Of insects would be a grea
aid In solving the problem and that the in
formation likely to be acquired by such lin,
OF research would be of the utmost practica
value In many other ways"