(437) 
• Thefame may bedone wida an ordinary Sea Compafs^ (o k 
iiave aGircle towards the Linib of the Card^ divided iqto De- 
grees, by fiiftening a fmall Thred , Lute-ftring or Wire (not of 
kon) fo upon it 5 as to pafs joft over the Center of thatCircle^ 
and placing aftraitpiece of Wood orBrafs-wire perpendicular on 
theedgeof theBox at theend of the Thred, and turning it to the 
Sun, tilltheShadow ofitfall juft upon theThred : then obferve^ 
what Degree of the Circle on the Card^ the Thred cuts ^ by 
looking plum upon it and that is the Suns Magnetical uiz^i^ 
mnth.. , 
But to have the Variation to Degrees and Minuter ( which is 
moft defirablej then theObfervation laft mentio.n'd. iTOft be raadis 
with a Quadrant y Sextant J or fori|e )liich otfer JnftFutaenti (o 
large as to admit of thedivifion of tl^egree ix^o ^hnwtes-^ which 
willrequke t\'\t Radius to be about threefoot theiargjer thebet-^ 
ter. If a ^adrant^ then, it being laid flat > and th.e; Square Bo}^ 
with the Needle placed upon it , move the ^0drant tQ'^nd a,gai% 
till that fide of it, on which the Box is placed, lie parallel to the 
Needle , when at quiet : - T ,the Stg^ of the .^^md(a^ being. 
flid.along the Rimb of it V' tilt' the Sun iliine/on bom its fides at 
the fametime, the. Mid-Line-) that divides equally the Sight ^ 
whentheSun fliines upon it thorovv the flit , will mark the Degree 
and Minuteof the Suns Magmiul 4z>mutk.:^MlmM^ 
beputinpra^ftjce, ■ \:- :^jm(v:spo •'■ 
And if many fuchObfevatbris be madeby kvarai peiii)^ 
the fanve place, and by the fame or other perfons difiaM^froai one 
another;, 1. 10.20. orniore Years.-, Not only will the. Gampafs: 
become more ufefulthanformerly, event© be .condilcye jioflibiy 
to the finding, the Lpngitud;e: at Sea,: ;at leafl' in tfo 
tKe variation of i' the variationof the Needle ibeirg.knowMD 'dif- ^ 
ferent places, all will be reduced to Rules, and fofrom jieiaca, fRhi- 
lofbphicalor Natural Knowkdge,. will^probabS^^ be-^nlmggduby a 
happy, difcovery, of the^tme cm^^M^^^^'^^uBy^ou)^ 
faculty of the Lotdftp^i)e,-| on^ of? Mh^ NMe'^^d md^moM d'/frufe L 
Fhanomerjaj that fiills under the cognizance of humane Rcafon. 
To find this variation by the Stars, is fo eafie, as every A/Iafter 
can do it ^ feeing there is no more requifire, than to find out the 
uue North^ that iSj xliQMeridiany ?.nd compare the Needles pofici- 
on 
