The times. [volume] (Washington [D.C.]) 1897-1901, 1901-01-13
ture of a birds wing. thus increasing
THAR aPHeicoov

ture of birds wing. thus increasing
their efficiency.
Another kite sometimes used at Blue
Hill IL Lamson ''aero-curve folding
kite" invented 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. 1t is
more powerful but less steady than the
Hargraye kite, and when used in a tan
dem is usually sent aloft as the leader.
with the Hargrave kites below to give
stability in addition to their proportion
of lifting power.
The Great Blue Rill-its summit the
division between two towns. Canton and
Milton. on the dividing line of which the
Observatory stands-command5 a beauti-
full panorama of sea and plain. from Cape
Ann, forty miles seward. to Grand Mo-
nadnock Mountain. sixty-eight miles dis
! tant in the West A kite flight from its
summit is not only a picturesque but en-
impressive spectacle: but the course OF
the experiments has many times been in
terrupted by the loss of kites and instru-
ments. the lines parting, and the kites
travelling on the wind to every part OF the
great plain below. Sometimes they are
recovered by the observers, but often
they 60 so great distance that they can
be followed only 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 rate of about a mile min
ute, as was determined by timing it
through a glass. Sometimes they come
to the ground with such violence that
they are utterly wrecked, instrument and
all; but usually they light SO gently that
If found again, both kite and inStrFRent
are little or not at all injured.
Steel piano wire is used as string" as
the best combination of strength and
lightpess. The windlass on which the
line is reeled, however. presented the
most difficult problem of all in the first
experiments. If one winds a bit of string
loosely about the finger a number of
times, the pressure. as everyone knows,
VIII finally become intolerablc In the
sane way the gathering coils OF the steel
wire oXeTted such force or the wooden
drum first used that il was literally
crushed out of shape, and The heads of
the BOLTS holding together the ends were
torn off by the tremendous pressure.
Finally Modification of Lord Kclyin's
steam power windlass for doep-sea sound
ing was devised by Mr.. Ferguson. which
after many experiments has proved en-
urely successful. Simply stated the plin-
clple IS pulley over which the kite wire
is conveyed TO 4 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 pow
er is used to draw the wire back. The
length of wire paid out and the pressure
eAerted-necessary to be known in order
to calculate how many more kites. if any,
can be safely added to the tandem-are
automatically registered.
Kites arc attached from time to time
as the wire tends to sag more and more
end 10 approximate. near tie windlass. a
horizontal ls1e. Each additional kite,
therefore. after the first IS released, OK
erts its power partly in sustaining the
main line and taking of the strain from
me leader. and partly only in elevating
ire instrument itself. The instrument
called meteorcsraph, is a combination
c. a rived TO include. compactly and with
tse IL fst possible weight. the various self
recording Instruments which are used TO
INVESTIGATE the aerial conditions For
mcrly 1t was suspended from the wire,
but It was found that greater stea1iness
could be secured If it were attached di-
rectiy TO il: and this is now done. The
meteorograpn includes an thermometer, for
recording continuously on a cylinder of
paper the velocity of the wind, the diree-
s,cn OF which is determined by the obser-
yations taken every minute from below,
or at night is more roughly calculated 10y
the shift of the wire at the windlass; an
alcohol thermometer, the contraction or
expansion Of which constantly changes
the curative OF the tube itself furnishing
q second continuous record; a microscope,
consisting Of a little bundle of human lair
one OF the most sensitive substances fer
the purpose-which lengthens in moist
and shortens in dry air currents: and a
self recording barometer TO ascertain at
mCspheric pressure and hence the height
in clouds or at night. In clear weather
and in the daytime the height nf the kite
is determined by observation of the angle
and from the length of the wire, after
eliminating the error caused by the sag
ging. averaging about per cent
Ordinarily a kite flight at Blue Hill lasts
from six TO eight hours. though it may
continue throughout a day or even the
night For some time the flights have ia
ken place monthly, on several successive
days in order to study the changing
weather conditions at different heights
The last was December 20. The statistics
of kite flights at the observatory are con-
veniently given in the small table prepar-
ed by Mr.. Rotch, as follows: