New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1894-12-27

altitude Of the observer and The desc,inat.9n Of the
body he OF the deslnaOn circle the axis OF me ne
the body. from rising TO setting. The Angular m
is pointed a, body in the sky. Us altitude Is DC
may be read from the instrument. instead of making
a long calculation as with an altitude observed by
set is the latitude the hour ang,e\and azimuh
are also correct If the latitli was ncorrcct men
a second observation viii make apparent me ldc,:
series Of observations requiring fifteen or twemy
longitude and true direction OF the mcridian com,
binin2 in the series all That IS solved ny summer
prime vertical 1t will be difficult to determine the
latitude, 1t viii he d!fiicult TO determine i on ne
degree Of accuracy in most cases. II the latitude
is known one observation will always Determine
time is known one observation will fix the latitude
and azmuth. II the true aziruth ;. appAIen'' Oh
observation vii, determine the latitude ana l''u
t.n", a. OF fbroo Oh .eryat;1ns VIII tx them
accurately The telescope has consiicrihe ina&nl-
flying power. affordns GeeIee Of accuracy IN IN on
he sextani 4 small electric lamp OF one candle
power Eliminates the crosshairs IN ~" tr'.S'p'.
and another lamp of four c'ndlc-power furn,shiss
light to read the graduated arcs 30 that observing
stars at night is not incony .nlenL a., i~,r,,
,nent and observer from the wind and Weath
This is cylindrical in shape, feet IN diameter, ana l
foot high and is holted 20 the dec., The middle
part revolves on the base ava IS ionr zee, n'tn
and 3 feet high rests. with ono side IN IN" same
cylinder plane as the other parts = u"oi
from nfteen inches above The deck 10 the tor
There are two sliding doors in the up'er part
opposite the main door, which are "imilar -
design TO the slit In an observatory dome, ~
wind shield is fixed across the opening o. nlI
sliding doc. which can be raised To any oesli,,u
extent The object Of the deckhous" IS primarily
to protect the instrument. ard incidentally TO per
nil OF observations being taken under all conl-
ons of sea and weather. For instance. IN ch ease
the sun or star ~ directly ahead. the snip
rolling deeply and fresh wind blown; rom lHuI.
ward. the instrument may be sheltered rom w.
obst,uct the view of the body 10 be observed
The principal part % tn" structure b"ns or" lvot
less In diameter ena1 - Wow o. star III tne
so that the top of the house viii not oh9'ruc' the
view.
TO determine the compass error Of a vessel a
o,Sideration to which Lieutenant Eeohlrr 'i,
fachcs much importance in mCGcr1 iron and steel
ships il Is necessary that the man ~ -"
wheel note the exact heading OF 80" mn al ihr
instant OF an observation MS can -" com u" ;,
signal such by an electro" bel Ihe'' ar" 'N'
POINTERS fixed to the outer bowl IN tho plane o. t,"
ships keel. these indicate ~" luhpnr Hn" "l lhr
shin. The float. hcine Icrir'tlF 'l'' !" S"ln
the bowl. and the axis 90 tn rod i'ai supports
the instrument s not always I'm o." same Nrrli. ~
plane tho tNo POINTERS Attached 10 IN. ""l,i
bowl At the instant % an OhsoIvauon ihe op-
server SIMPLY presses the two hinge! pointers on
the aZmuih circle, he notes The Tim" ~ M Ntl'I.
and reads the points whore tho TWO pointers meet
ings is equal 10 i,1 degrees. tho axis OF I'D" i"!
was in the plane o. the POINTERS. ana the reading
% the forward pointer vii show tn true direction
in which the snip was heading al me lhSl UT
OF the observation. II the sum OF the Two read
ings Is lcss than Isl dccrccs. the hi-i "ii'I'.
between that sum ana 80 should Dc aio'I 10 'h'
direction IN which the slip was heaAihE a., 'Ir
tine OF the observation. The dinerencr between
the true direction shown by he solar on, t'F ana
the course by the compass VIII b. Ire compass