Evening star. [volume] (Washington, D.C.) 1854-1972, 1928-09-02

airplane above the airport. allowing an
error of but few feet, is being StudSed.
/ The present day barometric altimeter.
which Is measure of atmospheric pres
| sure. is not accurate enough for the
purpose. and as it measures height
above sea level and not height above
| the earth. 1t has particularly grave dis
| advantages for flying across mountain
/ Gus country.
| A few months ago two Army Reserve
| pilots were flying through fog over
around in the fog until their gasoline
was exhausted trying to find clear
space through which to make a land
ing. Without instruments to tell them
of their accurate height above the
ground or water. they were unable to
make safe landing and crashed. In
StrumentS and an airplane inherently
stable under abnormal conditions prob
ably would have saved them.
Experiments of fascinating interest
are being undertaken by eminent sci
entiStS looking toward the development
by several means of sensitive altimeterS
to measure accurately the height above
the ground One is the development
of the SonSic altimeter This Is an in
strument in the airplane which meas
plane to the ground and back to the
instrument in the plane. The princi-
pie was successfully. used for submarine
detection in the World War. Another
device. the capacity altimeter, an in
strtIment In the airplane. indicates dis
lance from the ground by a measure of
| the electric capacity change between
two plates in the airplane as 1t ap-
| proaches the earth. Still another. the
radio altimeter Is designed to register
and measure radio waves sent from the
airplane to the ground and back To the
| airplane.
| Leonardo da Vinci, the great master
| OF all times, earliest scientific expert
menter in matters aeronautic. would
| indeed be thrilled with the neat con-
struction of this highway for aerial
| progress
| THE fourth problem is In the pene-
tration OF the fog by light rays.
| Much work of fundamental nature
still remains To be done and will be
done In this field A light from tube
filled with neon gas, known as the neon
, light. Is considered In n slight measure
effective through smoke fog found over
cities, but not SO effective through more
| pure water log.
An Army pilot who Elves to tell
the tale" tried his skill at fog penetra-
ton. He had been following railroad
track for miles. convenient method of
navigating in thick" weather Sud
denly" he says, "the railroad track dis
appeared like magic and | crashed on
the side of mountain" The railroad
track had passed through tunnel
under it,
This dissipation of fog. y Nth obiee-
tive, has been the subject OF laboratory
experimentation long before the advent
! of the airplane, and authorities agree
that It is perfectly feasible. but also
economically unsound. The methods pos
Sible on n fairly large scale are the
| sprinkling of fog With electrified sand
or spray. or the drying or evaporating
of fog by heat The conclusion that Ii
! Is economically unsound may be the re-
suit Of the study OF plans for fog dissi-
patton over great areas in citJ like
/ London. for example. or may possibly I've
based on an erroneous opinion OF the
needs of aviation without the results
OF further experimental work now being
carried on, one is unable 10 say. How
ever. the pilot of an alrplane once d.
reeted To = isnding field covered With
fog would he extremely grateful for even
small aperture down which he could
spiral to safe landing,