For finding whereof, every Expert Mariner is inftrudied , or may 
be fo 5 from his Sea- Books, and foit needs not here to be fet 
down. ^ Nor how by the help of thefe , the Azimuth required 
may^to Degrees , if nox nearer , be found out upon a goodcloke 
ox Planiffh^re^ (whereof thereisadefign tohaveone,thatis , the 
Anakmma^ contrived into a form of Inftrument for the ufe of the 
publick 5 and that erelong-, which will with great facility perform 
all that the Globe cando , with much more exadlnefs and conve- 
niency) that being fufficicntly known ^ 
But to do it accurately, you muftconftitute a^S/^r/V^/ obliqpte- 
angled Triangle y of the three Complements ^ oi iht Suns Decli- 
nation ^ lis Altitude ^ and o( thQ Height of the Fi^le-j theraeafures 
of all the Sides whereof are known > One from the ^r^7?/>//to the 
Fole^ .mother horn the Pole to the Point of the Suns Altitude and 
the third;) from that point to the Zentth. Now by r hofe you,arc to 
find out the Angle at the Zenith , which being found ^ fubftracfl it 
from i8o 3 and the remainder is the Suns true Azimuth ^ or Di- 
ftance from the of the Place, 
This Angle is to be found divers wayes , as by the Taidesof 
Sines, Logarithmes^ &c. the manners of doing whereof;^ are fee 
down and demonftrared by ^ohn Newton \n his Infiitutio Ma- 
thematicay Cafeii. and in other Books of Trigonometry. 
And the true Azimuth of the Sun being thus found, and the 
^agnetieal Azimuth oiit ^ according to your Needle, obferved, 
lubftrail the lefler Number from the greater , and the Remainder 
is the Variation of the Needle. If the Magnetical Azimuth be 
lelTe than the other , then the Variation is towards the fame fide of 
the Meridian^v/here the Sun is-, if greater, on the other. 
Toobfervethe Suns Azimuthby theT<leed\e, and the. Needles 
Variation to Degrees , any Needle, long enough to afford upon a 
Card under it, a Circle divided ii>to Degrees ^ put in a Square 
Eox , after the ordinary manner of C//;^4/(?wi , will ferve turn 5 
by pliCing the Box fo , as the Sun may fliine upoa any two oppOr 
lite fides of it , at the fame times that the Suns Height^ &c, w 
taken: For then the Needles Diftance from the Diameter of the 
C ircle on the Card , that .is parallel to thofe fides., is the Magne- 
tical Azimuth rec^wed, 
Ths 
