The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1901-01-13

from slipping through. The Joints of the
frame work are wrapped together with
string and glued, and the whole is strength
ened with fine wire running from angle to
angle in every direction, But both frame
and wiring are arranged with the greatest
care TO keep everything symmetrical, the
least deviation of either causing the kite
to fly wide and become manageable. In
the later kites the lifting surfaces have the
curvature Of a birds wing. thus increasing
their efficiency.
OTHER KITES USED.
Another kite sometimes used at Blue hill
Is Lamson's "aero-curve folding kite" in
vented by Mr.. c. H. Lamson. of Portland,
Me. Instead Of two boxes there is one,
with curved walls and a tail with surfaces
convex to the wind taking the place Of the
lower box. It Is more powerful but less
steady than the Hargrave kite. and when
used in a tandem is usually sent aloft as a
leader. with the Hargrave kites below to
give stability in ABOLITION to their proper
ton of lifting power.
The great Blue hill-its summit the d.
vision between two towns, Canton and Mil
ton, on the dividing line OF which the OBJ
servatory stands-commands a beautiful
panorama of sea and plain, from Cape
Ann, forty miles seward, to Grand Monad-
mock mountain. sixty-eight miles distant in
the west. A kite flight from its summit
is not only a picturesque. but an impressive
spectacle; but the course of the expert
ments has many times been interrupted by
the loss of kites and Instruments; the lines
parting and the kites travelling on the wind
to every part of the great plain below.
Sometimes they are recovered by the OBJ
servers, but often they go so great a dis
lance that they can only be followed
through the telescope, and getting them
back depends upon their return by some
person who happens to find them when
they light. Not long ago one was carried
to bingham. twelve miles distant. at a rate
OF about a mile a minute, as was deter
mined by timing it with a glass. Some
times they come to the ground with such
violence that they are utterly wrecked,
instruments and all: but usually they light
so gently that, If found, both kite and in
strument are little or not at all injured.
Steel piano wire is used as string as
the best combination of strength and
hghtness. The windlass on which the
line is reeled, however. presented the most
difficult problem of all in the first expert
ments. If one winds a bit Of string loosely
about the finger a number of times, the
pressure, as everyone knows, will finally
become intolerable. In the same way the
gathering coils of the steel wire exerted
such force on the wooden drum first used
that it was literally crushed out of shape
and the heads OF the bolts holding to-
gether the ends were torn off by the ire
mendous pressure. Finally a modification
of Lord Kelvin's steam power windlass for
deep sea sounding was devised by Mr.. Fer
gusson, which after many experiments has
proved entirely successful. Simply stated
the principle is a pulley over which the
kite wire is conveyed to a storage drum,
the coils on which are thus protected from
the strain of the kite. The pull of the
kite is sufficient to unwind the drum; the
power is used to draw the wire back. The
length of wire paid out and the pressure
exerted-necessary to be known in order
to calculate how many more kites, If any,
can be safely added to the tandem-are
automatically registered.
DELICATE INSTRUMENTS.
Kites are attached from time to time as
the wire tends to sag more and more and
to approximate, near the windlass, a hori-
zontaI line. Each additional kite, therefore,,
after the first is released, exerts its power
partly in sustaining the main line and TAX
ing off the strain from the leader, and part
ly only in elevating the instrument itself.
The instrument, called a meteorograph, is
| a combination contrived to include, COM
pactly and with the least possible weight,
the various self-recording instruments
| which are used to investigate the aerial
conditions. Formerly it was suspended from
the wire, but it was found that greater
steadiness could be secured If ii were at
tached directly to it,; and this is now done.
The meteorograph includes an thermometer,
for recording continuously on a cylinder of
paper the velocity of the wind. the direction
OF which is determined by the observations
taken every minute from below, or at night
is more roughly calculated by the shift of
the wire at the windlass; an alcohol Their
mometer, the contraction or expansion of
which constantly changes the curative of
the tube itself. furnishing a second con-
tinuous record; a microscope, consisting of
a little bundle of human hair-one of the
most sensitive substances for the purpose
which lengthens in moist and shortens in
dry air currents; and a self-recording
barometer to ascertain atmospheric pres
sure and hence the height in clouds or at
night. In clear weather and in the daytime
the height or the kite is determined by
observation of the angle and from the
length of the wire. after eliminating the
error caused by the sagging, averaging
about 2 per cent.
Ordinarily a kite flight at Blue Hill lasts
from six to eight hours. though il may
continue throughout the day or even the
night. For some time the flights have
taken place monthly, on several successive
days, in order to study the changing wealth
er conditions at different heights. The last
was Dec. %.
TIL highest flight, 1880 feet for the me-
neurological, or. for the kite above, about
one hundred feet more. 1t was made July
10 of last year. This is something over
three ~miles-higher than Mount Blanc, for
example. Meteorological observations in
balloons have been made by means of six
kites, a Lamson as leader, and five Har-
graves as wheel horses at distances of
from 1900 to $500 feet apart. 1t is possible
that on some future occasion four miles
may be reached, though the difficulties in
crease greatly with altitude.