Bor finding whereof, every Expert Mariner is inftru&ed or may 
befo, from his Sea* Books,, and foit needs not here to be fee 
down. Nor how by the help of thefe , the Azimuth required 
may, to Degrees , if not nearer, be found out upon a goo & Globe 
or Plahifphare, (whereof there is a defign to have one,that is , the 
Analemma , contrived into a form of Inftrument for theufe of the 
publick , and that erelong-, which will with great facility perform 
all that the Globe can do , with much more exadhrefs and conve- 
niency) that being fufficiently known. 
But to do it accurately , you muft conftitute a Scried oblique- 
angled Triangle , of the three Complements , of the Suns Decli- 
nation , its Altitude , and of the Height of the Pde 5 the meafures 
of all the Sides whereof are known $ Gnefrom the Zenith to the 
Pole * another from the Tele to the Point of the suns Altitude 5 and 
the third, from thatfoint to the Zenith. Now by rhofe you are to 
find out the Angle at the Zenith , which being found , fubftraft it 
from 1 So , and the remainder is the Suns true Azimuth, or Di- 
fiance from the Meridian of the Place. 
This Angle is to be found divers wayes , as By the Tables of 
Sines, Loganthmes , the manners of doing whereof, arefet 
down and demonftrated by fohn Newton in his In fit utio Ma- 
thematical Cafe 1 1. and in other Books of Trigonometry . 
And the true Azimuth of the Sun being thus found, and the 
Magneticd Azimuth of it , according to your Needle, obferved, 
fubftradl the letter Number from the greater , and the Remainder 
is the Variation of the Needle, If the. Magnet ical Azimuth be 
lefie than the other , then the Variation is towards the fame fide of 
the Meridian, where the Sun is 5 if greater, on the other. 
To obferve the Suns Azimuth by the Needle, and the Needles 
Variation to Degrees , any Needle, long enough to afford upon a 
Card under it , a Circle divided into Degrees , put in a Square 
Box, after the ordinary manner of Clinatories will ferve turn * 
by placing the Boxjfo , as the Sun maylhine upon* any two oppo- 
site fides of it , at the fame times that the Suns Height, &c. are 
taken: For then the Needles Diftance from the Diameter of the 
Circle on the Card , that is parallel to thofefides , is the Magne- 
tic d, Azimuth required. 
