ABSTRACT
Thefabrickeofthefra1neisthus:Firstofallthereisa Base,orfoottorestupon,onwhichthereareraisedperpendicularlysixeColumnesorPillarsofequalllengthanddistance;uponthetopofwhichthereisfastenedtoalevell andparalleltotheBasearoundplateorcircleofwood,ofa sufficientbreadthandthicknesse,whichtheycalltheHori-
Horizon.zon,becausethattheuppermostsuperficiesthereofperformeth theofficeoft.hetrueHorizon.Foritissoplacedthatit divideththewholeGlobeintotwoequallparts.\Vhereof thatwhichisuppermostrepresentethuntousthevisible Hemisphrere,andtheothe1·thatwhichishidfromus.So likewisethatCirclewhichdividesthatpartoftheworld whichweeseefromthatotherwhichweeseenot,iscalledthe Horizon.Andthatpointwhichisdirectlyoverourheads inourHemisphrere,andisoneverysideequidistantfromthe Horizon,iscommonlycalledZenith;buttheArabiansname itSemith.Butyettheformercorruptednamehathprevailed, sothatitisalwaysusedamongWritersgenerally.Andthat pointwhichisoppositetoitinthelowerHen1isphrerethe ArabianscallNathir;butitiscommonlywrittenNadir. ThesetwopointsarecalledalsotheP~lesoftheHorizon.
