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under the investing sphere, every star in the celestial sphere becomes correspondent to another place upon the earth, and so on, until the earth has com*pleted one diurnal revolution; or till all the stars, by their apparent daily motion, have passed over every meridian of the terrestrial globe. From this view of the subject, an amazing variety, uniting in wonderful and astonishing harmony, presents itself to the attentive reader; and future ages will find it difficult to investigate the reasons that should induce the present race of astronomers to neglect a subject so highly interesting to science, even in a practical view, but which in theory would lead them into more sublime speculations, than any that ever yet present

ed themselves to their minds.

A GENERAL DESCRIPTION OF THE PASSAGE OF THE STAR MARKEDY IN THE HEAD OF THE CONSTELLATION DRACO, OVER THE PARALLEL OF LONDON,

The star, in the head of the constellation Draco, having 51 deg. 32 min. north declination, equal to the latitude of London, is the correspondent star thereto. To find the places which it passes over, bring London to the graduated side of the brass meridian, and you will find that the degree of the meridian over London, and the representative of the star, passes over from London, the road to Bristol, crosses the Severn, the Bristol channel, the counties of Cork and Kerry, in Ireland; the north part of the Atlan

tic ocean, the Streights of Belleisle, New Britain, the north part of the province of Canada, New South Wales, the southern part of Kamschatka; thence over different Tartarian nations, several provinces of Russia, over Poland, part of Germany, the southern part of the United Provinces; then, crossing the sea, it arrives again in the meridian of London.

When the said star, or any other star, is on the meridian of London, or any other meridian, all other stars, according to their declination and right ascension, and difference of right ascension (which answers to terrestrial latitude, longitude, and difference of longitude), will, at the same time, be on such meridians, and vertical to such places as correspond in latitude, longitude, and difference of longitude, with the declination, &c. of the respective

stars.*

From the stars, therefore, thus considered, we attain a copious field of geographical knowledge, and may gain a clear idea of the proportionable distances, and real bearings, of remote empires, kingdoms, and provinces, from our own zenith, at the same instant. of time; which may be found in the same manner as we found the place to which the sun was vertical at any proposed time.

Many instances of this mode of attaining geographical knowledge, may be found in be found in my father's treatise on the globes.

* Fairman's Geography.

OF THE USE OF THE CELESTIAL GLOBE, IN PROBLEMS RELATIVE TO THE PLANETS.

The situation of the fixed stars being always the same with respect to one another, they have their proper places assigned to them on the globe.

But to the planets no certain place can be assigned, their situation always varying.

That space in the heavens, within the compass of which the planets appear, is called the zodiac.

The latitude of the planets scarce ever exceeding 8 degrees, the zodiac is said to reach about 8 degrees on each side the ecliptic.

Upon the celestial globe, on each side of the ecliptic, are drawn eight parallel circles, at the distance of one degree from each other, including a space of 16 degrees; these are crossed at right angles, with segments of great circles at every 5th degree of the ecliptic; by these, the place of a planet on the globe, on any given day, may be ascertained with

accuracy.

PROBLEM XXXVIII. To find the place of any pla net upon the globe, and by that means to find its place in the heavens, also, to find at what hour any planet will rise or set, or be on the meridian, on any day in the year.

Rectify the globe to the latitude and sun's place, then find the planet's longitude and latitude in an

ephemeris, and set the graduated edge of the moveable meridian to the given longitude in the ecliptic, and counting so many degrees amongst the parallels in the zodiac, either above or below the ecliptic, as her latitude is north or south; and set the centre of - the artificial sun to that point, and the centre will represent the place of the planet for that time.

Or fix the quadrant of altitude over the pole of the ecliptic, and holding the globe fast, bring the edge of the quadrant to cut the given degree of longitude on the ecliptic; then seek the given latitude on the quadrant, and the place under it is the point sought.

While the globe moves about its axis, this point moving along with it will represent the planet's motion in the heavens. If the planet be brought to the eastern side of the horizon, the horary index will shew the time of its rising. If the artificial sun is above the horizon, the planet will not be visible: when the planet is under the strong brass meridian, the hour index shews the time it will be on that circle in the heavens when it is at the western edge, the time of its setting will be obtained.

PROBLEM Xxxix.

To find directly the planets which are above the horizon at sun-set, upon any given day or latitude.

Find the sun's place for the given day, bring it to the meridian, set the hour index to XII, and elevate the pole for the giyen latitude: then bring the place

of the sun to the western semicircle of the horizon, and observe what signs are in that part of the ecliptic above the horizon, then cast your eye upon the ephemeris for that month, and you will at once see what planets possess any of those elevated signs; for such will be visible, and fit for observation on the night of that day.

PROBLEM XL. To find the right ascension, declination, amplitude, azimuth, altitude, hour of the night, &c. of any given planet, for a day of a month and latitude given.

Rectify the globe for the given latitude and day of the month; then find the planet's place, as before directed, and then the right ascension, declination, amplitude, azimuth, altitude, hour, &c. are all found, as directed in the problems for the sun; there being no difference in the process, no repetition can be necessary.

OF THE USE OF THE CELESTIAL GLOBE, IN PROBLEMS RELATIVE TO THE MOON.

From the sun and planets we now proceed to those problems that concern the moon, the brilliant satellite of our earth, which every month enriches it with its presence; by the mildness of its light softening the darkness of night; by its influence affecting the tide; and by the variety of its aspects,

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