New-York tribune., 1909-09-26

performing similar feats in aeroplanes. the i'm
portant problem of determining the astronor-
zeal position of these craft becomes evident
During the daytime, while the earth Is IN
view, 1t IS possible for an experienced acrOnaut
70 locate where he Is by means OF charts. and at
night he can be guided more or less by the
lights OF cities or towns. He can also use the
friendly stars as his guides. We can see in the
future classes formed for learning the constella-
tons, especially the nine conspicuous "nautI-
cal stars used by nautical men for dctcrmIn-
ing their longitude at sea. Their names are
ArIetIS. Aldebaran, Pollux, ReguluS, Spica NIr-
GINS. AntareS, Altar, Fomalhaut, and Narkab.
The true places of these stars for every day
in the wear are given in the Nautical Almanac.
a valuable work published annually two or
three years IN advance at the United States
Naval Observatory at Washington, for the
benefit of sea Captains engaged in long VOYAGES
Difficult to comprehend q 1t NAV be, vet 1t Is
a well known fact that the skilful navigator
who should be lost on an unknown sea, or in
the midst of the Pacific Ocean, can. by meaStir-
the distance between ArletiS and the moon,
which often passes near 1t, determine at once
not only the spot he Is in. but his true co rse
and distance to any known meridian or harbor
on earth.
That man." writes Sir John Herschel.
by merely measuring the moons apparent dis
tanCc from a star with a little portable IN
strument held in his hand and applied to his
eve, with so unstable footing as the deck of
ship, shall say positively within FIVE miles
where he Is on a boundleSS ocean. cannot but
appear to persons ignorant of physical astron-
omy an approach 10 the miraculous And vet
the alternatives of life and death wealth and
ruin. are daily and hourly StaLed with perfect
confidence, on these marvellous combinations "
Captain Basil Hall relates that he had sailed
from San Bias on the west coast of Mexico and
after a voyage of eight thousand miles OCCt1Dv-
ing eighty-nine davs. arrived off Rio Janeiro
having in the interval passed through the
PaC1ilc Ocean, rounded Cape Horn, and crossed
the South Atlantic, without making anv land
or seeing a single SAIL on the voyage Arrived
within a few days sail of Rio he took a set of
lunar observations, to ascertain his true po-
Sltlon and the bearing of the harbor and
shaped his course accordingly. As a result of
his calculations. he had to alter the course only
about point in order to hit the entrance of
Rio. This was the first land he had seen for
three months, after crossing so many seas. and
being set backward and forward bv innumer-
able currents and hard winds
A Pilot of the Sky
FOR navigational purposes, it is lust as i'm
portant To know exactly where one Is when
travelling through the air as it Is to a sailor
when his ship Is plowing the ocean An able
book written for the benefit of aerial vovagers
has Just been published by Professor Adolf
MarcuSe, who IN this way has assumed the
responsibility of being a pilot of the skv.
lie draws attention TO the fact that aero
nautS should make themselves ACQUAINTED
WITH tle ways ana means tor navigating the
arr; tor the subject will increase in importance
as the years 90 by. The instruments necessary
tor the determination of longitude and latitude
are the level quadrant for the determination of
altitude, Chronometer for recording Green
wlch time and fluid compass for azimutb
observations With no glimpse of the earth
beneath him, the only two facts he has in ms
possession are his height from the ground and
the magnetic cardinal points
In spherical balloon, this knowledge does
not inform HIM whether he is travelling in a
northerly. southerly, casterlv OF westerly DIRE
ton In dirigible he NAV head his craft IN
the direction OF any point of the. Cornrass.
but then his leeway will be an unknown Guan-
tity, or he will soon find that his position IN
relation 70 the earths surface is unknov-n
Possibly better observations can be made
however. from the platforms of dirigibles than
from the baskets of spherical balloons In the
hrSt place. the basket of a balloon IS seldom,
steady, and IS nearly ALWAYS in a state of sI,U,
rotation Again. the envclop above the oh.
server cuts OH a considerable portion of The
SKY that would be available under sea or Iand
conditions; but. against this he is in an 81
waited position and his horizon is clearer H..
can form talr estimate OF his position wbetber
north, south east or west If he has a knon,1