The Providence news. (Providence [R.I.]) 1891-1906, 1893-11-28
D. AihLLItS rAl y
sly QUAKER OATS
eooMERANes.
How They Are Thrown and the Mochan-
ical Theory of Their Flight.

How They Are Thrown and the Mochan-
icai Theory of Their Flight.
There are two kinds Of bOomcrangs-one
Of which Is commonly cnilcd the come
back boomerang" from the strange pecu-
liarity oe its flight, while the other iacallcd
"barngect" The latter is used in war and
in the chase, and Is about feet inches iI
length and weighs about l2 ounces. IL is
slightly curved and resembles scimeter IN
shape The "barngect' or war boomerang
Is pointed OH both ends and is thrown TO
kill or wound large game, such as the kan
garoo and the Australian wild dog and hu-
man foes. IL Is not made TO return TO the
thrower. The Apache Indians OF Arizona
employ similar weapon in hunting rab-
bits. It's form varies from that of caval-
ry saber to an obtuse angle OF lS0 degrees.
IL is about 90 inches long, inches broad
and thin at the edge.
IL Is rather difficult 20 explain the me-
chanical theory of the fight OF the BOOM
erang. First-The rotation Of the instru-
ment about its free axis through the CEN
ter of gravity is the fundamental condition
OF success. The faster the rotation the
longer the boomerang floats in the air.
SeconA-FAe- mutation of the axis Of rota.
tion has To be considered. This mutation
decreases with the angle OF inclination OF
ahe two wings Of the boomerang, and in
creases with the increase of the said angle.
In the case of small angle the plane OF
potation keeps parallel TO the initial posi-
hon of this plane, or very nearly so. The
two wings form one plane with their lower
sides (thisa angle being zero). The instrument
has no perceptible mutation, and must be
thrown perpcndicularly TO the vertica.
plane passing through the hand. The in.
strument then rises and returns nearly to
the same plane that it went up. This
throw is rather difficult.
In the second case, the angle OF inclina-
ton of the two wings being very large, the
plane of rotation is constantly changing in
regard TO its inclination with the horizon,
and by this circumstance causes the instru-
ment TO describe a series of fSmplicated
curves like those of a large bird of prey
before it settles at the feet of the thrower.
In general the initial plane of rotation
must form an acute angle with the horizon,
which may increase to right angle when
the inclination of the two wings is nearing
its maximum.
Professor Eggers has formulated the fol-
lowing directions for throwing the boomer
ang: Take the boomerang with the full
fist by one end SO that the flat side of the
instrument faces the ground, and then fling
it away with outstretched arm, giving it at
the same time rotary motion by jerk
with the wrist. In the moment OF leaving
the hand the boomerang should have an in
clination toward the left, and its progress
= sive motion should be in an upward direc-
tion under certain angle OF elevation
The angle of inclination to the left and the
angle of elevation vary from one instru-
ment to another and have to be ascertained
by some gentle trial throws for any par
ticular instrument before the thrower ap-
plies the full power of his arm. The field
for practice should be soft ground, free of
stones or other hard objects. Throw it
against the wind or half against it. Do not
practice when hard wind is blowiNg."-
New York Telegram.