dian, which is the fun's place for the day required; . and by comparing it with the calendar on the horizon, the correfponding day will appear.

EXAMPLES.

What day is of the fame length as the 20th of March-Anf. The 23d of September.

What day is of the fame length as Jan. 6Feb. 28-March 9-April 30-May 22-June 11July 1-Auguft 12-Sept. 16-Oct. 17-Nov. 14 -and Dec. 17?

PROBLEM XXVI.

To find upon what Points of the Compass the Sun will rife and fet, in a given Latitude, upon any particular Day.

Rectify the globe for the affigned latitude; find the fun's place in the ecliptic for the given day; bring it to the Eastern verge of the horizon, and that part of the mariner's compass then in contact with the fun's place is the point upon which the fun rifes on that particular day; and by revolving the globe till the fun's place touches the Western edge of the horizon, the point on which the fun fets will appear.

EXAMPLES.

On what points of the compafs does the fun rife and fet at London, lat. 51, at the vernal and

autumnal

autumnal equinoxes ?-Anf. Exactly on the Ea and Weft points.

N. B. This answer will ferve, at those season of the year, for any place which is fituated in t torrid, or either of the temperate zones, who latitude, of course, cannot exceed 66 deg. Nort or South.

But it must be remarked, that the days now ad verted to, are the only ones on which this cz poffibly happen; for at all other times of th year, the fun at its rifing and fetting recedes from the East and Weft points, in a greater or lei degree, according to its declination and the various latitudes for which the globe may be rectified, as will plainly appear by folving the following quef tions. The greatest recefs of the fun from the Et and Weft points, at its rifing and fetting, is at the fummer and winter folftices. While the fun is in the Northern figns it rifes between the Eaft and North, and fets between the Weft and North points of the compafs and during the time this luminary is in the Southern conftellations it rifes between the East and South, and sets between the Weft and South points of the compafs. From the folution of this problem then, the pupil may learn to avoid the vulgar error of thofe perfons who fpeak in unqualified terms of the fun's rifing in the Eaft and fetting in the West.

Required on what points of the compass the fun rifes and fets at London, lat. 51 North, at the fummer and winter folftices; at St. Vincent's Cape, lat. 37 deg. Jan. 16; at London, Feb. 3; at Kinfale, lat. 51 deg. March 22; at Londonderry, lat. 55 deg. April 20; at St. Andrew's, lat. 561, May 28; at Pomfret or Pontefract,

lat.

lat. 53, June 13; at Rheims, lat. 491, July 17; at Carrickfergus, lat. 54, Aug. 13; at Rouen, lat. 49, Sept. 9; at Rotterdam, lat. 52, Oft. 28; at Leicester, lat. 521, Nov. 28; and at Ambleteuse, lat. 502, Dec. 23.

PROBLEM XXVII.

To know at what Hours of the Day the Sun will be due Eaft or Weft, the Latitude of the Place and the Day of the Month being given.

Rectify the globe for the given latitude; bring the fun's place to the meridian; fet the index to noon: fix the quadrant of altitude in the zenith, bring it to the Eaftern point of the horizon, and turn the globe round till the fun's place touch its graduated edge; the hour to which the index then points, is the time when the fun is due Eaft: bring the quadrant to the Western point of the horizon, and turn the globe till the fun's place touch its graduated edge, and the hour to which the index. points, is the time when the fun is due Weft. Or, if the globe have a double hour circle, the first of the operations will folve the problem; for, as the fun is always due Weft the fame number of hours after noon, or mid-day, as it is due Eaft before mid-day, this coincidence is at once indicated by the index of a double-hour circle, e. g. fuppofe the fun fhould be due Eaft at any place at 8, 9, or 10 o'clock in the morning, the correfponding hours would be 4, 3, and 2; and thefe would be the periods when the fun would be due Weft on that day.

EXAMPLES.

EXAMPLES.

At what time is the fun due Eaft at London, lat 51 North, at the vernal and autumnal equinoxes Anf. Six o'clock in the morning.

At what time is the fun due Eaft at Kimbolton lat. 52, Jan. 8? at Edinburgh, lat. 56, Feb 10 at Stockholm, lat. 59, March 29 at S Auguftin, in Florida, lat. 30, April 2? at Prague lat. 51, May 6? at Bannockburn, lat. 55, Jun 25? at Londonderry, lat. 55, July 31 at Port mouth, lat. 50, Aug. 23? at Floudenfield, lat 551, Sept. 9? at Aix-la-Chapelle, lat. 51, Oct. 7 at Petersburgh, lat. 60, Nov. 17? at Rome lat. 42, Dec. 30?

PROBLEM XXVIII.

To find all thofe Places which have the fame, or th contrary Hours of the Day, with a given Place.

Bring the propofed place to the brazen meridian and obferve what places are then exactly under the Eastern fide of that femicircle of the meridian and all thofe places have the fame hour of the day*.

To find thofe places which have contrary hours, bring the affigned place to the meridian, and fet the index at 12; then turn the globe till the index points to 12 on the oppofite fide of the hour circle, and all thofe places which then lie under the Eaftern fide of the upper femicircle of the meridian will have oppofite hours. Or the problem may be

* See page 34.

›lved in the following manner : Reckon 180 derees either Eastward or Weftward on the equator, om the given place, and obferve what places have he fame longitude with the part of the equator has found; places fo fituated have oppofite hours o the one proposed. Again, the fame anfwer may be thus obtained: Obferve the longitude of the iffigned place and find another in the oppofite longitude, whofe longitude added to that of the given place will make 180 degrees: e. g. if the given place has 50° of East longitude, a place fituated in 130° of Weft longitude will have oppofite hours; or if the propofed place has 30° of Weft longitude, another which is fituated in 150° of East longitude will have contrary hours, being 180°, or half the circumference of the earth, afunder.

EXAMPLES.

What places have the fame hour of the day as London?-Anf. Bourdeaux, Valencia, Oran, the Shetland Islands, and part of the Gold Coaft, nearly.

What places have oppofite hours of the day to Vera Cruz?-Anf. Madras, Pondicherry, Tranquebar, and Candy in the ifland of Ceylon; thofe places being 180°, or half the circumference of the globe, from Vera Cruz.

What places have the fame hours of the day as Dantzick, Morocco, Algiers, Tunis, Calcutta, Botany-Bay, Pekin, Owhyhee, Panama, Aftracan, and Borneo ?

What places have oppofite hours to the following places: London, Edinburgh, Dublin, Paris, Madrid, Lisbon, Amfterdam, Bruffels, Bern, Vienna, Berlin, Rome, Conftantinople, Warfaw, Peterfburgh,

Bergen,