Navigatipn “ by its edges ;to the upper part of fesmall hem&pherlcal
^llowjsea {^sup^t o&(?h^ame metal<, turned downwards The: qup,,
" i‘iao..iiM8etvted,vservesiaSi8> socket-»<tdfffe^^iye 4 steekpjjyot
“ irising-fram a Paviiy made intp^a round pieee.ofdigbt
■ “ A&ddd^'QpEcurk, which thus form's the comp&ss^>.oX’.
*T)he|surfacces}df*the®>©kee,and pivot, intended!-to ffieet
“ each other, ar.e perfectly-polished, tQravoidXlasknuchdts
“ possible; ,all ^ietinn. The;p«p ha's? a -proportionably
abroad! margin, which* beside- addingrjtO'uEsv weighs
“ tendsTromiits hprizontal position toa’kqa|hthe^een tee sof
“ gravity, in all situations of the compasg^,pearly in 500-
“ incidencejwith tbe 6ep‘tretfofisuspension. The^aydty,
I in! which the .needle j^ithus-suspended, is inform. ei®-
“icular,.and is littlCut®tp.than suffipientfto recei,ygjthe
“ needle*,cup, and-pivot. -Oyer this^avityisplaegldh thin
“ pieeeoftranspatenttalc, which prbyeUfsftheneedlefroaaa
“ being affected by an^ motion of the external ai^lbut
m petipits thesapparent motion of the fdfiKer.t® be easily
‘j observed.j The^hiall and short m^U^ff the.Qkij^'p
“ has a material adytotag^bver those ofthe usual sizgin
-1 e :Europe,^pvith regard to the inclination, or- dip toward?
“ the horizon $ whichr in the latter, peguirds that one
■?* .extremii^tE tbe ne^pte^hould be made so much hea-
“ vier than the other, -as, will counteract thu magnetic
m attraction. This:being.,different in ‘different parts of
“ the world, the needle; can only.be accurately true.,at
“ thepla^ybr which it had been constructed, Butin
“ short and light needles, suspended after the Chinese Navigation
“ manned; the' the point of suspension, Yellow sea.
^Ts,moré‘thàn sufficient^ overcome the magnetic power
.tïÉbf-ihe dip'ter inclination, in alf'situations of the glcfbe ;
and therefore - such hfedlfeV' \#ill 'never^deviate from
‘1 feir^hori;^
%U'p® the upper surface of the box are' drawn, as'ap-
pehfs in the' arihexe'd engraving, Several concentric lines
'or circlesl-aOcoMing fbvthé^kr iSiih Sifes5 of th||pbmpass-
box. This is isè'Mbm less than fbür^inéffi's in diameter!
Tl® circled are’"di|>ti^msBc(3‘by different >®ffinesc'î*t^ ;
râetefk Eight arêmarkeulffi the first or innermoslTciïele ;
fouf'bf whi€h denote the' càfdiri’al',points of ;ea’St, ,-west,