2. Move the Brass Meridian (keeping the Body of the Globe fixed as before) higher or lower, until 49d. 57m. on it do cut the Horizon (on the North-fide thercof) then is the Globe rectified to the Latitude of the Lizard: The like you must do in rectifying the Globe for any other Place, or Latitude.

3. Screw the Quadrant of Altitude to 49d. 57m. on the Brafs Meridian, which is juft over the Lizard, (if the Globe be not returned from it's Pofition as in the firft Step hereof,) and turn the graduated Edge of it to Barbadoes, the faid Edge will Point on the Horizon to 69 Degrees South Wefterly; which is the Angle of Pofition of Barbadoes from the Lizard; that is, the Angle, the Arc of a Great Circle, paffing through or over the two Places, makes with the Meridian of the Lizard, which is not the Rumb, leading from the firft to the second; for, if you rectify the Globe, to the Latitude of Barbadoes, and fo proceed as before directed, you will find the Angle of Pofition to be 38 Degrees North Eafterly, the Pofition of the Lizard from Barbades, which is 31 Degrees less than the Pofition of Barbadoes from the Lizard; whereby it appears neither of thefe are the true Rumb, or Point of the Compafs leading from one Place to the other: For you are to Note;

1. That the Rumb-lines, or Points of the Compafs, make equal Angles with all Meridians on the Globe.

2. That an equal Segment, or Part of the faid Rumb, changeth, or alteret the Latitude in all Places equally.

3. That the Rumb-lines, though continued ever fo far, do not pafs into, or through the Poles, but wind about them 'till they lofe themselves.

4. Thefe Rumb-lines are reprefented upon the Globe by those Spiral-Lines, which you fee are 32 in Number, meeting in a Center, where there is a Flower-de-Luce pointing to the North; from whence they run winding about the Globe, and continue inclining towards the Pole, where they feem confused.

Problem 5. Two Places being given; to find their Rumb, Bearing, or Courfe in Sailing from one to another.

The Rule. 1. Having found the two Places on the Globe, fee what Rumb Line paffeth through both of them, and that is the Rumb, or Course from one to another.

2. If no Rumb-Line pafs through both Places, then observe that which runneth parallel to both Places, and that is the Rumb, or Course from one to the other.

Example

I demand the Courfe from the Lizard to Cape Cod in New England?

On the Globe you will find thefe Places to lie on the W. by S. and E. by N. Rumb Line, and therefore the Course from the Lizard to Cape God, is W. by S. and confequently from Cape Cod to the Lizard E. by N.

Example 2. I demand the Courfe from the Lizard, to the Inland Barbadoes?

Here no Rumb Line on the Globe paffeth over them; wherefore look for a Rumb to which the Place lies moft parallel, and you'll find it S. W. half W. the Course from the Lizard to Island Barbadoes; and NE. half E. from Island Barbadoes to the Lizard. Problem VI. Courfe and Distance failed being given; to find the Difference of Latitude and Difference of Longitude.

The Rule. 1. Make a small Mark on that Rumb Line (which is the given Courfe) in the Latitude of the Place you fail from, bring that Mark to the Brafs Meridian, and it cuts the Equator in its Longitude.

2. Take the Distance failed from the Equator, and lay it on the faid Rumb, from the forefaid Mark; at the Termination thereof make another Mark.

3. Then bring this Second Mark to the Brass Meridian, which is the Latitude of that Place; and then the Meridian cuts the Equator in the Longitude of it.

4. Having the Latitude and Longitude of those two Places marked in the Rumb Line, by Subtraction you may find their Difference of Latitude and Difference of Longitude, and it is done.

Example. Suppofe a Ship fails S. W. by W. 200 Leagues, or 10 Degrees from the Lizard: I demand her Difference of Latitude, and Difference of Longitude; or what Latitude and Longitude she is

in?

1. Make a Mark on the S.W. by W. Rumb, juft under 49d. 57m. (the Lizard's Latitude) and then the Meridian cuts the Equator in 5d. 14m. W. the Longitude of that Mark.

2. Take 10 Degrees from the Equator, and lay it on the SW. by W. Rumb, from the First Mark to the Second Mark.

3. Bring the fecond Mark to the Brafs Meridian, and the Latitude of it is 44d. 40m. the Latitude the Ship is in, and in the Equator the Longitude of it is 17d. 59m. W. by Subtraction, the Diff of Lat. is 5d. 17m. and Diff. of Long. is 12d. 45m. Longitude in this, and all the fucceeding Problems being estimated from the Meridian of London. But here you muit note: L

That,

That, The Distance failed intirely taken, and laid on the Rumb, is the Distance in the Arc of a Great Circle, and not really in the Rumb; for the Distance in the Great Circle is always lefs than the Distance in the Rumb: Wherefore, the better Way will be to take 1, 2, 3, or (or fome fmall Number of) Degrees of the Equator; and run that Distance (in the Compaffes) over, upon the Rumb Line from the First Mark to the Second; and in fo doing, the Distance is more truly laid, then by taking

it at once.

Problem VII. Both Latitudes and Courfe given; to find the Diftance and Difference of Longitude.

The Rule. 1. Turn the Body of the Globe 'till the given Rumb doth cut the Brafs Meridian in the Latitude you depart from, and there make a Mark on the Rumb, and at the fame Time, fee what Degree of the Equator is cut by the Meridian; for that is the Longitude of this Mark.

2. Turn the Body of the Globe 'till the fame Rumb cuts the Meridian in the Latitude of the second Place, and there make another Mark on the Rumb; then fee what Degree of the Equator is cut by the Meridian, which is the Longitude of the fecond Mark; and the lefs Longitude fubtracted from the greater, gives the Difference of Longitude required.

3.

The Distance between the two Marks on the Rumb Line, being measured (according to the Note in the laft Problem) on the Equator, gives the Distance of the two Places.

Example. If a Ship fails SW. by W. from the Lizard, 'till by Obfervation fhe is in Latitude 44d. 40m. North; I demand her Distance failed, and what Longitude she is in?

1. Bring the SW. by W. Rumb to cut the Meridian in 49d. 57m. the Lizard's Latitude, and make a Mark on that Rumb there, then the Meridian cuts the Equator in 5d. 14m. W. the Longitude of that Mark.

2. Turning the Globe 'till the SW. by W. Rumb cuts the Meridian in 44d. 40m. the Latitude of the fecond Place, and inaking there a Mark on the Rumb; then the Meridian cuts the Equator in 178. 59m. W. the Longitude of the second Mark; and therefore the Difference of Longitude, is 12d. 45m. Weft; which being adding to the Longitude of the Lizard, 5d. 14m. W. the Sum is 17d. 59m. W. the Longitude the Ship is in.

3. Take 2 Degrees from the Equator, and run over that Ditance in the Compafles upon the Rumb, from the first

Mark to the Second, and 'tis five Times, which is 10d. or 200 Leagues, the Distance failed on that Rumb.

Problem VIII. Having the Latitude, and Longitude the Ship is in given; to find the Place where the Ship is in, on the Globe.

The Rule. 1. Bring the Longitude to the Brass Meridian, and there ftay the Body of the Globe.

2. Where the given Latitude cuts the Globe, make a Mark on the Body of the Globe, which Mark is the Place of the Ship at that Time.

Example. If a Ship fails S.W.ly, from the Lizard, and after fome Time is in Latitude 44d. 40m. Longitude 17d. 59m. W. I demand the Place of the Ship on the Globe?

1. Bring 178. 59m. W. on the Equator to the Brass Meridian, and there ftay the Globe.

2. Juft under 44d. 40m. N. on the Brafs Meridian, make a Mark on the Body of the Globe, and that is the Place of the Ship at that Time.

Section III, The Defcription of the Coeleftial Globe.

THE

HE Cæleftial Globe reprefents that glorious Canopy, fo richly embroider'd, and befet with those sparkling Diamonds, that upon the dusky Cheeks of the Night hangs as rich Jewels in an Ethiopian's Ear; having upon its Convexity artificially placed all the Stars, correfpondent to their Natural Situation in the Con cavity of the Orb, which we call the Starry Heavens.

2. The Appurtenances belonging to this, are the fame with thofe belonging to the Terreftrial Globe; and being before defcribed in Section I. of this Chapter, I refer you to it.

3. On the Body of the Globe, befides the Constellations, there are drawn diverfe Circles; as the Equinoctial, Ecliptic, Colures, Meridians, and Circles of Longitude: All these are called Great Circles. The leffer Circles are the Tropics, Polar Circles, and Parallels of Declination.

4. The Equinoctial in this, is the fame with the Equator in the Terreftrial Globe, and in the fame Manner divided, and number'd from the Left-hand towards the Right, with 10, 20, 30, &c. to 360 Degrees.

The Poles of the Equinoctial are alfo called the Poles of the World, and are represented by the two Wires on which the Body of the Globe turneth.

L 2

5. The

5. The Ecliptic is a great Circle which croffeth the Equinoctial in two oppofite Points, the Beginning of Aries, and Libra; it is divided into twelve (equal Parts called) Signs, each containing 30 Degrees, and figured from the Left-hand towards the Right, 10, 20, 30; then 10, 20, 30, &c. having the Figure, Character, and Name of each Sign, as followeth ;

This Circle with its Figures and Characters, are on both Globes; but the Coeleftial hath the Images and Names of the Signs, which the Terreftrial hath not.

Under this Circle the Sun moves in his Annual Course; but the reft of the Planets have their Deviations from it; for which Reafon Aftronomers have affigned eight Degrees on each Side the Ecliptic, making the whole Latitude to be 16 Degrees, which Breadth is called the Zodiac.

The Zodiac is not drawn on the Globe, only imagined by two "Circles parallel to the Ecliptic, at eight Degrees Distance from it, on each Side thereof.

The Poles of the Ecliptic, are two oppofite Points, each 23d. 29m. diftant from its correfpondent Pole of the World: In these the Circles of Longitude all meet, and near each is writ Polus Eclipticus.

6. The Meridians are the fame as before on the Terreftrial Globe, only with this Difference, on this they are drawn thro' every 30 Degrees of the Equinoctial, on that through every 15th Degree of the Equator; in both they all meet in the Poles of the World.

7. The Colures, are two Meridians, cutting each other at Right-angles in the Poles of the World, dividing the Equinoctial and Ecliptic into 4 equal Parts; the one paffeth thro' the Beginning of Aries and Libra, the two Equinoctial Signs; therefore called the Equinoctial Colure; and on the Globe it is divided into Degrees, numbered from the Equinoctial both Ways, 10, 20, 30, &c. ending in 90 at each Pole of the World: It generally hath thefe Words near it, Colorus Equinoctiorum.