The Use of the Globes.

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These are the chief Problems 0 f eCelejlial Globe; We now proceed t0

E P the Axis of the Ecliptic,

N AS an Hour-Circle or Meridian,

ZAD an Azimuth Circle,

E Y P a Circle of Longitude.

sz I 25 the Ttopic of Cancer.

kf kf the Tropic of Capricorn. val

2. By Means of these Circles various Spher 1 ^ tt 1 ^

angles arc formed for Calculation. Thus MPlace of the Sun in the Ecliptic ; then in th sangled Triangle A X C we have , e f

C A the Sun’s Place , or Longitude from tnox C.

AX the Sun’s Declination North.

C X the Sun’s Right-Ascension. r;*«V> H

A C X the Angle of Obliquity of the ^

3. And supposing the Sun rising in the Hor'

cm the Lay of the Summer Tropic, and N M fp f j tSoCircle ; then there is formed the Right-angl eN O M, in which we have s.

N O =Æ Z — the Latitude of the P' aC ^M O the Amplitude from the North.

N M the Complement of the Sun’s

ONM the Ange of the Hour from M 1

O M N the Angle of the Sun’s Positi° n ’ , \ ^ ^

4. On the fame Tropical Day the Sun 1S , ‘ pjoss©’Clock, because the Hour-Circle of >ht-^upon the Axis NCS; therefore in theTriangle I C K we have

I K the Sun’s Altitude at Six.

C K the Azimuth from the Eaft atC I the Declination North.

XC K the Latitude of the Place.

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to

KJl tut- X , C ul A t ls 1t>

Again ; when the Sun on the fame i si

' ' -- ’ due ,L,W

Vertical Z C D, his Place whenLt O ; therefore in the Right-angle'e have

he Sun’s Declination North. ,»,/j,

'.e Sun’s Altitude when EaR r>r r