( 6Si )

9. For Rectisylng this in forne measure (and of fome other Inconvenien-cies ) Mr. PVright adviseth, that (the Meridians remaining Parallel, as before )the Degrees of the Latitude remote- from the Equator, üiould at each Paral-lel, be protracted in lilse proportion with thole o !t ■ Longitudo.

10. That is; As the Co-Sine of Latitude (which is the Semidiameter cfthe Parallel) to the Radius of the Globe , (which is that of the Equator :) Sofhould -be a Degree of Latitude (which is every where equa! to a Degree.of Longitude in the Equator,) to such Degree of Latitude so protracted (at suchDistance from the Equator;) and so to be reprefented in. the Chart.

ii: That is;.every where, in such Proportion as is the rcfpective Secant(Tor such Latitude ) to the Radius. For, As the Co-Sine, to the Radius; sois the Radius, to the Secant (of the fame. Arch or Angle;) os 2 : R:: R: s F ' s ' 207 ’

11. So that (by this means ) the Position of each Parallel in the Chart?

{hould be at such Distance from the Equator, comparcd with so many-Equi-’noctial Degrees or Minutes,.( as are those ot Latitude ) as are ali the Secants-( taken at equal Distances in the Arch ) to so many Times the Radius.

15. Which is equi valent ( as Mr. PVright there notes) to a Projectiomofthe Spherical Surface.( soppofing the Eye at the Center ) on the ConcaveSurface of a Cylinder erected at Right Angles to the Plain of'the Equator.'

14. And the Division of Meridians, reprefented- by the Surface of a Cy- Fg;.2o5»Under erected ( on the:Arch of Latitude ) at Right Angles to the Plain of

the Meridian. (or a Portion thereof.) The Altitude of sich Prdjection ( cr'

Portion of such Cyliudrick Surface) being, (at each Point of such Circular'

Base ) equal to the Secant ( of Latitude ) anfwering to sich Point.

15. This Projection ( or Portion of the Cylindrick Surst.ce ) if expanded F&. 20?.into. a.Plain, will bethe fame with a Plain Figure, whose Base. is equal to aQuadrantal Arch extended (or a Porlion thereof ) on which ( as. Ordinat es)

are erected Perpendiculars equal to the Secants, anfwering to the refpqctiye-.

Points of the Arch so extended : The least of which ( anfwering to the Equi- :noctial) is equal to the Radius ; and.the.rest conrinually increasmg, till- ( atthe Pole) it be Infinite.

16. So that, as ERSL. (a Figure of-Secants. erected at Right- Angles on«

EL, the Arch of Latitude extended ) to ERRL, ( a Rectangle on the fameBase, whose Altitude ER is. equal. to the Radius;) so is EL (an Arch of the 1Equator equal to that of Latitude ,). to the Distance of such Parallel, ( in the-Chart ) from the Equator.

17. For finding- this Distance, anfwering to. each Degr.ee and Minute of-Latitude, Mr. PVright ( as the most obvious way ) Adds all the Secants ( as -they are found calculated in the 'Trigoncmetrical Canon ) from ■ the beginningto the Deg. or Min. of Latitude propofed.

18. The Summ of all which exceptthe Greatest,-( anfwering to the.Fi-

guro Inscribed.) is too.littlec The Summ of ali except the Least, (anfweringio. the Circumfcribed) is too Creat; (which is that He follows: ) And ic [would be nearerto the Truth than eirher, if ( Omirting. ali thefc ) we takethe Intermediäres ; for Min. i, i|,'..i|>. or ( the double of thde )

Min. 1, z, y, 7, Lfc. Which yet (becaufc.on the Convex-side of the Curve)wculd .be fomewhat too Little.«. 59t But

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