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G E o G
eJr poiol of lacilude. This done, bring Ihe filO'S plJCC in
lhe ecJlptic for Ibe giten day (found by Pro~ X ) to Ihe
gradu,ncd fiJe of Ihe brafen mcridiJn, ar.d fu Ihe hom·
inoex 10 XII al noon , which is Ihe uppcrmoll XII on Ihe
hour·circle; aod Iheglobe wi Ube rrétificd.
PkO B XVIL n, lalill/d, of allJ p:ace, nol ,xeud·
ing 66-\- d<grm , alld Ih, duy oflh, lIIonlh. bring giom;
/O ¡lid /l1e 1;111: oflun rijing and ¡-I/;ng, al/d eOllft·
9)(111" Ih, Imglh of lb, daJ and night.-Having re.2ifi·
ed Ihe globe for Ihe lalilude, aod for Ihe fun's place on
Ihe giveo day (as dlre.2ed io lhe precediog problem)
briog Ihe fun'; place in lhe ecliplic 10 lhe eallero fide of
Ihe horizon, aod Ihe hour·inde,~ wiU Otew die lime of
fun rifing; Ihen lurn lhe glube 00 ilSaxis, unlil lhe fuo's
place comes 10 Ihe werlern fid~ of lhe horizon, and Ihe
index wiU lItew lhe lime of Cuo.Ceniog.
The hour of Cuo·Cettiog doubled, gives Ihe leoglh of
Ihe day: aod lhe hour of fuo rifin;; doubled, gives lhe
bgth of the night.
P ROBo XVIII. 7¡', lalil/lJe of allJ 1'1"", and Ih, day
Df IhelIJon/h bring givm ; l . j'lId "'/¡'" Ih, lIJornillg I",i·
ligh b'gillJ, and Ih, ,wning /",ilighl rn,iJ, 011/"1plau.
-This problcm is Orteo limiled: for, wheo lhe Cuo does
OOt go 18 u<grccs bdow lhe horizoo, lhe lwilighl cooti·
nues the ",hule night ; and for Ceveral nights tegether in
lummer, bellVeen 49 and 66{ degrees of I,nitude; aod
Ihe nedrer to 66-\-, lhe grealcr is lhe numba of theCe
nights. BiIt wheo it does begio and end, .the foUow·
ing melhod wiU Olew the time for aoy given day.
Rcélify the gl"be, aod briog the fuo's place in the eco
Jiptic 10 the eallero fide of the horizoo; lheo mark lhal
poin! of lhe ecliplic with a chalk which is in lhe werlero
[¡de of the horizoo, it beiog the poiot oppofile 10 lhe
fuo's place: this done, lay the quadrant of altitud: over
Ihe Caid poinI, aod turo lhe glohe eaflward, keeping lhe
quad rant at lhe mark, unlil il be jurl 18 dcgrees
high 00 the quadraot; and the iodex wiU POiOI OUt lhe
when lhe moroing lwilight begins: for lhe Cun's
place will then be (8 degrees below lhe eaflern fide of
Ihe horizoo. To find lhe lime \Vhen the evening lwilighl
ends, briog lhe Cun's pl. ce 10 lile werlern fide of the ho·
, izon, and lhe poin! oppofile 10 il, whieh was m" ked
with the chalk, \ViJl be rifiog in the earl: lhen, bring lhe
quadrant over tltll point, aod keepiog il lhereon, lUro
Ihe globe \Vellward, unlil lhe Caiu poinl be 18 degrees
aboye the horizon 00 lhe quadrant, aod the index \ViJl
Otew the lime when lhe eveoiog lwilight ends; lhe Cuo's
place beiog lheo 18 degrees below the weIJern fide of lhe
horizoo.
P RO Bo XIX. 70¡ndon",hal d,,,oflh' J,ar Ih'fun
b'gil/J lo/hin. conJlall/~ " ftllillg , D'I all)' glwn
¡la" in Ih, norlhf rigid Z./I'; alld /10'111 I.,'g h, eonlinu:/
lo d. fo -Reélify lhe globe 10 lhe lalitude of lhe place,
aod turo it aboul until fome poinl of the ecliplic, be·
[IVecn aries and caocer, coinciues Wilh lhe oon h point of
lhe hOflzon where lhe brafen meridiao CUlS il : lheo find ,
00 lhe \Vooden horizon, what d"y of the year the fuo is
in lhal pnint of the eclilltic; for lhal is lhe day onwhieh
!he fuo begi os 10 lItioe cooflaotly on lhe giveo place,
WilhoUl Cttling. This done, luro Ihe globe uOliJl Come
.l0int of lhe eclip.tic, belween caoecr anu libra, cuincides
A p II Y.
\v;lh th. nonh poiot of lhe horizon, where the orafea
melidial1 cuts it ; ano fiou, on the \'Iouuen horizoD, 0 0
\Vhat u.,y the Cun is in th.t po;m of the ccliptic; \lhic
is lhe uay that lhe fun I:a. es all' cod!antly /hinlng Ol! the
f.¡jd place, aod riCes and ftts 10 i, a, te other pl.lces 00
¡Jle globe. The numbcr oC o~tu ral days, or compleal
revolutions of the Cun abo"t lhe earth, belween the tWO
days aboye found, is the lime lhat lhe Cun keeps conrlaol'
Jy ahove the horizon withoul feuing: for all ,h,1! poniotl
of lhe ecliptic, which lies bel\Veen the t'oYOpoints whi<;h
iOlerCeé! the horizm in lhe very nonh, ne' er Cm bclow
it: aod lltere is juHas much of lhe oppoGle pan of lhe
ecliptic thal nel'er riCes; therefore, the Cuo wiU keep as loog
coorlanuy belo\V the horizon inwinter,anbove it iDfumOler.
PRoa XX. 70¡lid i/l ,<,hal la/ilud, Ih. fU/I jhmu
miflanl" ",;Ihou/ fllling, jor ally I<I/glh of /il/" lefr
Ihall 18l l of our dayr alld n(¡'hl/.- Fi nd a poiot in the
erliptic half as many degrees fromlhe begi oning of caD·
cer (eilher tDw.,d aries or libr.) as lhere are nalural days
in the time giveo; and briog thal POiOI lOlhe nonh fiue
of the br.fen meridian, on which the dcgrees u e num–
bered fromthe poie lowards the equator : lhen, keep the
globe from turoing on ilSaxis, and Q,de the meridiao up
or down, until lhe point of the ecliptic comes 10
lhe nonh point of the horizon, and lheo the elevatioll
of lhe pole will be equal to lhe latilude required.
PRoa. XXI. '{h. lalilude of a pl.c<, nol ,wdin~
667 d'/lm /, and Ih, doy of Ih, month bring givM; I~
¡nd IOl luo'/ a/JIplillld•. Dr poilll of Ih, eompafr on ",hich
h, rifo/ or fm.-Reélify the globe, and briog the Cun's>
place 10 the eanero fide of the horizon; lhen obCerve
\Vhat point of the COfJpaCs on lhe horizulJ rlands right
ag,lin(l the Cun's place, for that is his amplitude al ri–
/i1>g. T hi, done, lUrn lheglobe werlIVard, uoti! the C~o's
place comes 10 the IVerlero fi de of lhe hQrizon, aod it wiJI
CUl the POill1 of his amplilude al fwing . Or, you maYo
count lhe rifiogamplilude io degrees, from the earl poiot
of lhe horizon, to lhal point where lhe Cun's place'cu ts
it; aod lhe C. tting amplimde, from lhe \Vd! po.iot cE.
Ihe horizoo, lo the Cun's place at Ccuing.
PROB o XXII. '{h, lalilude, Ih, f UI/'/ pl"c<, a~dhÍ1
"11;lutl,, bWl/1 giwn ; lo¡nd Ih, hour if Ih, doy, ami
Ih, fMn'/ azimulh, or IlUlllb" of degrm Ihal h, ir di–
Jlar.llrol/J Ih, me,idian -Reélify lhe globe, and briog
lhe CJn's place tu the gil'eo height upon the quadraOl oí
altilUde ; on lhe e,l(I, ro fiJe of lhe horiz0n, if the lime
be iD lhe forenoon; 0(' the "'efiern fide, if it be io lhe
arternoo¡t: lheo the iodex wilJ lIteIV lhe hour; anu lhe
oumber of degrees in the horizon, interCepled belweeD
lhe quadrant oi altitude and lite Couth POiOl, wilJ be the
fun's true azin1l1th al lhal lime.
r KOB. XXlJL 7h, I"lilud" hour of Ih, daJ, anJ
Ih, fun ') plnr:, ",in.~ .~iv", ; lo¡nd /h, (UII'/ a!ti/ud, .lId
azimulh -R eL~ify theglobe, and tnro it unlil lhe iodex
poin,s 10 Ihe gil'eo hour ; lhen Jay lhe quadraol of alli·
lude over lhe CUIl'S place in the ecliplic, aod Ihe drgrec
of the <¡uadran! CUl by the fuo ', place is his altilude a[
lhal time abore llie hori20n; and Ihe dC~l'a of the hori·
zon CUl b)' the quadrant is lhe Cun's aZlmlHh, le koncd.
frnO! the Coulh.
f IlO B. XXIV. 1h .. I'llilud" Ú'fm'} allilud" ad
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