The Hawaiian gazette., 1905-11-03

pheric conditions and their effect.
Given a shooter who holds steadily
and has good eyesight, the causes for
misses and for high and low shots,
other than as spoken of above may be
put under several different heads, to
wit: changes in temperature, in baro-
metric pressure. percentage of mois-
ture; wind and mirage; changes of
| light and personal equation.
Temperature: While a rise in tenn
perature of 1-2 degrees will cause
the ball to rise ten inches in 1000 yards,
the difference in the rise and fall of
temperature in these islands is so
small that while it should be taken
into account for the purpose of judy
Ing all conditions surrounding the
firing of shot. but little or no al
lowance will have to be made for it
here; still it should not be lost sight
of by one seeking to qualify himself
to become an expert
J Barometric Pressure: So, too, with
the barometer, a rise of a half an inch
will lower shot ten inches at 1000
yards, but the probable change in the
! reading of a barometer during the
firing of a score will seldom be suffi-
cient to justify changing the sights.
iOiNthtd6t VI EhOiSluIe Inc amount
of moisture in the atmosphere, rapidly
changing as 1t does in this climate,
has probably more influence on eleva-
tons than perhaps any other cause
When il is considered that seven and
one-half per cent of moisture will
cause a ball to rise ten inches in 1000
yards. II will be readily seen that with
our frequent showers the moisture in
the atmosphere changes so very rapid
ly that this element should be care
fully watched. So too If water gets
into the barrel and on the bullet the
amount of friction is reduced and ele-
walton raised and judging the result of
the shot Is then more a matter of
guesswork than anything else.
Wind and Mirage: DR.. Hudson in
writing of the match for the Palma
Trophy in which the Canadians de-
feated the Americans at Ottawa, Sep
TENDER 49, 1901. says: Weather con-
ditions We're good in the
morning and we profited by that fact
to the extent of gaining lead of
twenty-five points over the English
team at 800 yards. But in the after
noon, when the 800 yards stage was
about one-third completed very bad
weather conditions arose, with rapid
changes of light caused by clouds scud-
ding by; the wind came in fierce gusts,
veered continually from one point to
J another, and small but strong eddy
currents formed on the range. Under
these conditions with nearly every flag
pointing different direction, the only
reliable way of gauging the wind was
by observing the mirage through a
telescope trained on the target. This
the English team had found in three
weeks practice to be the only relia-
BILE way of gauging the wind on that
} range, while we were almost totally
unfamiliar with the method and had
J not even brought a suitable telescope
with us. The result was that the En-
, glishmen overcame our lead and gain
ed twelve points on us +"
} Since that match mirage has always
! been very strong factor in judging
the extent of the lateral detection of
| the ball. The speed at which the
bubbles" travel across the glass and
. the amount of mirage must be taken
into account in determining the speed
of the wind. and also the fact that
apparently the target to some extent
is displaced dts image seeming to be
carried along with the wind) which
the mirage increases. A head wind
carries the mirage down and a rear
wind up and as the mirage increases
or decreases allowance must be made
In the elevations in addition to that
made for the velocity of the wind.
Most marKsmen pay great deal of
attention to the detection of the ball
to the right or left as influenced by
the wind, but apparently pay little or
no attention to the retarding or ac-
celebrating influence. With such winds
to contend against l think too often
the rise or fall of the ball was due
more to his having taken a finer OF
coarser sight than usual and not give
due weight to the influence of the wind
As is stated in the small arms firing
regulations: I'm considering the ac-
ton OF the wind upon the flight of the
: proJectile the rifieman Is at once met
! with two-fold problem. He must de-
T, termine the probable effect upon ele-
vations and upon reflections or devia-
, tons. To arrive at any satisfactory
. conclusion II is necessary TO consider
the wind force resolved into two COM
: ponent forces. one acting in the plane
/. or nre, the other at right angles to
1t. 1t Is then possible to make the re-
quired allowances. essentially as iftwc
: independent forces were acting, each
having a constant uniform direction