An introduction to astronomy: designed as a text-book for the use of students in college. By Denison Olmsted ...

~1.0~1 S ~ H'1E11E MOON.
to ]avet a sufficient hior1izolntal extent to beconie visibe, thley
can hardly be sul)posed to attatin thle necessary e levation, wh)cen
we efleoct thlat the heighlt of the gieat pyramiti of Egypt is less
thtan tiel sixthl part of a mile.'IIXXASAeS 01 PuNtll MOtON.
21 1. TheI'l chalnges of the 1moon, commonllly ealled her
Pl}asel, arisr: from diflrelent porltions of her hilllminated side
bteing turne toward tthe. eartth at different timls.'When tle
m1oon0 is firslt,seen after thle settilng' sutn, her form is that of a
bligholt cresectt, on thl e side of thle disk next to the stlll while
the otlher portions oft thle disl shlinte withl a tfeeble Elight, reflected to t}:o mloon fitom the earth. Evlerly Inighlit wtYe observe tile
moon to be further at(nd furtfler eastwarid of the suln, and at the
satne ine tihe c'eescent enlarglh es, 1lutil, when it has reacthed an
clolr'ation f'omin tle still of nearly 90, htallf her vliil)le disk is
et'lgtenled, anld shle is aid to 1be in her1' tJ/int t.itartlr.'l
telrm1ilnator, or line which l searates the illuminated from +
dark palrt of the moon, is convtex toward thle sun firom t.
new 1110oon to tlle first quar-ter, and tlte o 0oonl is saitl to b)e
/&t ied(. The extremities of tile crescent are called ct.ss'. A t
the fillst quarter, the terminator beeomnes a straig'it Iili, coillcidintg witlh a diameter of the disk; but after lpassing tlis
i)oint, thel ter-minatoir bccl.lles colncalve towarcl tlte still, boundinr; tloat sitie of thle moon by an elliptical curve, whenit toe
jtimoot is saidt to )oe ibbous.'Whten the moon atrives at tile
distance of 180~ f'0111 the 5slls thelt entire circle is illumlinatCd,
anld the tlmoon is fall. She is tlhen it o)pp)ositio, to tle sullt,
risillg about tlhe time tilet stun sets.:t'or a week after tle full, tleo
11oon0 appears gibu))ll0s agaill? lutil, at a little less than 90~)
frlom tho sull, slte itctumles1 tile satc firm as <at the lirst quctttler,
heim' ttlen at 1elr thir w/ qaItr. F1om this tille ullltil IICNw
1moo(t, she lexhibits again thlic ft01 of a curescent beiore tlhe
risinlg sll until. appro.aching her eoy uiocion wittn tilhe su,,
etr Inarrowt) tlhreadC of lighlt is lost in thle solar blaze; and finally, at tlte IltolellIt of )assin tel l s tile da iik side is wholly
ttulld tltoward its (aId for so11 e timue we lose siIgrht of the 111001oo.'rThe two points in the orbit corresponding to new anlt full
Ittoon respectivel y, are called by thle commnoin la1e of syz.yyies;