Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-03-29

at its highest in the heavens, but it was
nowhere to be seen. Dark clouds shut
out every ray from this blazing ball of
light. The sea was as Somber as the
sky, while a great ocean liner, bound for New
York, wes nosing its way somewhere in the vast
Atlantic
Just IS seamen have done every day for some
500 years, the officers stood waiting on the
bridge with their sextants ready to shoot" the
solar disc and so locate the position Of the liner.
With the sun beaming down they could measure
where they were and the ship could be pointed
accurately on her course. But high above lay
. heavy haze of cloud and fog.
Compass errors and currents shift even the
mightiest vessels from their way upon these
watery tracks and the noontime check is inn
pogtant to head the ship precisely toward its
port of destination. If this fog curtain hung
stubbornly between the ship and the sun the
skipper would have recourse but to make the
best guess he could and, using series Of calcu-
lations, locate himself by dead reckoning.
SO Columbus and John Cabot, Hendrix Hud-
son and Magellan, with less charts and lesser
mathematics, had also fumbled and figured
when nature was hostile and chose TO keep the
sun out of sight.
But breeze blew. the clouds parted and the
sun beat through. The four men, sighting their
sextants "shot" the position of the sun and
each man reported his findings Of the latitude.
The two extremes were found to be one and
half minutes apart. In this latitude a minute
of distance on the map is mile. The four
readings were averaged and the mean was taken
the true position of the liner
A TRUNK stood on the bridge. An upright
rod rose from it holding q metal drum.
Beneath the drum hung a sextant, and as the
clouds closed in again and the sun once more
disappeared behind the blackness, Paul Hum
phrey Macnei the inventor, stepped up to the
apparatus.
He turned q few screws and dials and q
needle swung back. and forth until finally it
reached the maximum a graduated scale.
He turned it over to Capt s. G. s. Mcneil of
the ship for reading The captain of the ship
and the inventor have names of the same pro-
nunciation. but spelled differently.
The skipper gazed at the scale in astonish-
Fnent why" he exclaimed, 1T is within one
minute Of the correct latitude"
How do know what is correct?" asked
Staff Capt F. w Robinson who was also
on the bridge. Our sextant observations vary
a. much one minute and a half, while this
instrument is only minute away from the
average reading of our four"
With the sun completely obscured, a sextant
reading locating the position of ship by the
position of the sun had been taken for the FIRST
time in the long history of navigation.
"I really believe" said Mr.. Macneil that the
all-weather sextant more accurate than the
observations taken by the four officers with
their hand instruments. Their reading was
subject to human error, while mine was taken
by q mechanically and scientifically accurate
instrument"
Mr.. Macneil's combination of wires and
fights glass metal and gelatin is the first real
advance in this phase of the art of navigation
since mariners began To use q simple cross bar
steadied by hand to take observations Of the
sun and translate them with nautical tables into
the latitude Of that spot on the sea.
The cross bar developed into the astrolabe