inch, and with one foot in a, set off this distance, 9 times from a to A, also from a F, from a I, and from a D, and mark the divisions, each of which will contain 10 degrees.

Extend the compasses from a to A, and strike the circle AFI D, each quadrant or quarter of which, as from A to F, must now be divided into 9 equal parts, in the following manner. With the same extent in your compasses, with which you struck the circle, and which is called the radius of the circle, set one foot in A, and the other will mark the division at d; also, set one foot in F, and the other will mark the division at b; thus the quadrant A F becomes divided into three equal parts, each of which, as Ab, &c. must be carefully divided into three other equal parts. The same with each of the other quarters of the circle.

-The circle and the diameters being thus divided into 36 equal parts, each of which contain 10 degrees, it only remains to draw the parallels and the meridians, and these divisions are the points through which the parallels and the meridians are to be drawnWhat remains is extremely easy, provided these divisions have been accurately made.

First, to draw the parallels; begin at one of the poles, for example, the south; there are the three points e, c, i, through which to draw the arc of a circle, which shall be the parallel of 80° south latitude. This is done by adjusting one foot of the compasses on the line Da F, as at n, so that the other shall pass directly through the three points, ce i, and thus describe the arc ce i, which will be the parallel of 80° south latitude. This done, with the same opening of the compasses, draw the parallel of 80o north latitude. In the same manner all the parallels are to be drawn. In describing the next parallel, or that of 70°, one foot of the compasses will fall at f, while the other passes through the points 8 m p.

To draw the meridians; As all the meridians pass through the poles, consequently, to draw, for instance, the meridian of 800 W. longitude from London, adjust one foot of the compasses on the line A B, as at h, so that the other shall cut the equator at s, (80° W. longitude from London) and pass directly through the poles. Then describe the arc Fs D, which will be the meridian of 800 W. longitude from London.

In the same manner all the meridians are to be drawn, so adjusting one foot of the compasses on the line A B, that the other shall cut the equator at the proper division and pass through the poles. In describing the next meridian west, or that of 90o, the foot of the compasses will fall at ẻ.

The centres on which to describe these arcs may be found geometrically as follows; for the parallel of 60° N. latitude, with one foot of the compasses in o, and the other extended any length more than half the distance to w, describe the arc 2 2. With the same extent in the compasses, set one foot in w, and with the other describe the arc 3 3. Through the points of intersection draw the line lr, and where this line cuts the diameter or axis, extended without the sphere, viz. at x, will be the centre on which to describe the arc do w, which will be the parallel of 60° N. latitude. In the same way may any or all the centres be found.

OF THE GLOBES.

A Globe or Sphere, is a round body, every part of whose surface is equally distant from its centre.

Artificial globes are of two kinds, viz. the terrestrial, which exhibits a representation of the earth, with the natural form and situation of land and water; and the celestial, which has on its surface a representation of all the visible stars in the heavens, and the images or figures of all the various constellations into which these stars are arranged.

Each globe consists of the following parts, viz.

1. The Two Poles (being the ends of the axis on which the globe turns,) which, when applied to the heavens, signify the points directly over the terrestrial Poles. That which is visible to us is called the Arctic, or North Pole; and its opposite, the Antarctic, or South Pole.

2. The Brazen Meridian, divided into 4 quarters, and each quarter into 90 degrees. This circle surrounds the globe, and is joined to it at the poles.

3. The Wooden Horizon, which surrounds the globe, the upper part of which represents the true horizon, and has several circles drawn upon it; the innermost is marked with all the points of the mariner's compass; the next contains the names, characters, and figures of the twelve signs of the Zodiac, subdivided into degrees; and the third is a calendar of months and days. By the two last is instantly seen the signs and degrees the sun is in during every day in the year.

4.

The Hour Circle, divided into twice twelve, equal twenty. four hours, fitted to the brazen meridian, round the north pole.

5. The Quadrant of Altitude, which is a thin slip of brass divided into 90 degrees, corresponding with those on the equinoctial. It may be screwed on occasionally to the top of the brass meridian, to measure the distance of places.

OF THE CIRCLES ON THE GLOBES.

The circles on the globe are divided into Great and Less.~~Great Circles are such as divide the globe into two equal parts, as the Equator, the Ecliptic, the Meridians, the Horizon, and the Colures ; the Less circles divide the globe into unequal parts, as the two Tropics and the two Polar Circles.

The Equator or Equinoctial, commonly called The Line by mariners, is a great circle, divided into 180 degrees each way from the first or chief meridian; making altogether 360 degrees, if reckoned quite round the globe to the point from whence they begin This circle divides the globe into northern and southern hemispheres.

The Ecliptic is a great circle, cutting the equator obliquely in the opposite points of Aries and Libra, and is designed to represent that path in the heavens which the sun seems to describe by

the earth's annual revolution round it. It is divided into twelve equal parts called signs, which correspond with the twelve months, and each sign is subdivided into thirty parts, called degrees.

The names and characters of these signs, with the time of the sun's entering them, are as follows :

The Zodiak, so called, which is 16 degrees broad, (8 degrees on each side of the ecliptic) contains the above mentioned signs; from which the sun never departs, and within the bounds of which, all the planets perform their revolutions.

The Meridians are those circles that pass from pole to pole, and divide the globe into the eastern and western hemispheres. There are commonly marked on the globes twenty-four meridians, one through every 15 degrees, corresponding to the twenty-four hours of the day and night. But every place, though ever so little to the east or west, has its own meridian.

The first meridian, with English Geographers, is drawn through London.

The Horizon is that circle you see in a clear day, where the sky and the earth, or water, seem to meet; this is called the visible or sensible horizon, and is of greater or less extent according to the distance of the eye from the level of the earth. Thus an eye placed at the height of five feet from the surface of the earth or sea will merely have a prospect of two miles and a quarter around, supposing the earth to be perfectly level; but at the height of twenty-five feet it will receive a prospect of five miles and three. quarters. That called the rational horizon, encompasses the globe exactly in the middle, and is represented by the wooden frame already described.

The Colures are two great circles supposed to intersect each other at right angles in the poles; and are called, one the sol. stitial, and the other the equinoctial colure, because one passes through the solstitial, and the other through the equinoctial points of the ecliptic. The first determines the solstices; and the second shews the equinoxes; and by dividing the ecliptic into