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does the sun's distance from the meridian indicate the hour on the equator.

Example.-On April 12th the sun is seen. 63° high at London; what o'clock is it?

When I see the Dog star at Rome 20° above the horizon, on the 20th November, what o'clock is it?

When the middle star in Orion's belt has 32° altitude at London, on the 1st. of December, what o'clock is it popod

PROBLEM VIII.J 0067

To find the Latitude of a Place, by having the meridian Altitude of the Sun, or a Star, given, ‹ on a certain Day.

Rule. Find the sun's place in the ecliptic for the day, place a piece of paper on it, marking its center for exactness, bring the paper to the meridian, which(meridian) slide backwards and forwards till you have fixed the given altitude, then will the elevation of the pole shew the latitude.

Example.-If I am sailing on the Atlantic at twelve, on May 1st, and find by observation the sun's altitude 50°, what latitude am I in?

If, on the 27th Octobe, I see Arcturus pass over the zenith, what latitude am I in ?

If, at ten at night, I see Spica 60° above the horizon, on the 25th May, what latitude am I in?

On the 22d November the sun is in the first degree of Sagittarius, at ten this evening the Dog star is 12° above the eastern horizon,what latitude must I be in to observe this?

PROBLEM IX.

To find the right Ascension in Time of the Sun.

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Rule. Note, That the astronomical day begins twelve hours later than the civil day; so that the right ascension in time of the sun, is its distance from the first points of Aries estimated in time on the equinoctial, viz. 15°, to an hour...

Example. What is the right ascension in time of the sun on the 25th May?

What is the right ascension in time of the sun on the 25th September?

What is the right ascension in time and degrees of the planet Jupiter at this time?

PROBLEM X.

To find when the Sun rises or sets, at any Place, on any Day of the Year.

Rule.-Rectify the globe for the place given, find the sun's place in the ecliptic, bring that place to the horizon, and count the meridians from thence to the brazen meridian; and (if they are 15° asunder) it will be so many hours before noon when the sun will rise.

Example.-When will the sun rise to Lisbon on the 29th October?

When will the sun rise at Boston on the 5th June?

At what hour will the sun first appear to the inhabitants of Petersburgh on the 6th May?

PROBLEM XI.

To find when continued Twilight will begin in any Latitude between 50° and 60°) and how long it will continue.

Rule.-Elevate the pole to the latitude of the place given, then turn the globe, and observe where the ecliptic cuts the twilight wires, the day and month corresponding to that part of the ecliptic, is when the twilight begins, and where the other part cuts the wires will shew when the twilight ends.

Example. When does twilight begin to continue all-night at York?

When does continued twilight end at Berlin?

When may I begin to travel all-night to the eastward from Warsaw?

PROBLEM XII.

To find the Sun's Altitude for any Time of the Day, at the given place.

Rule.-Bring the place into the zenith, fix the quadrant there, turn the globe till the sun's place comes to the given hour, and lay the graduated edge over the sun's place, and there is his altitude.

Example.-What is the sun's altitude on May 10th, at nine o'clock in the morning, at London?

What is the sun's altitude at two, on the 5th November, at Paris?

How high is the sun, at twelve at night, to the inhabitants of the North Cape on Midsummer-day?

How high is the Polar star above the horizon to the people of Dublin?

PROBLEM XIII.

To find how much of the Heavens is inclosed by the Circle of perpetual Apparition in any Part of the World.

Rule. The circle of perpetual apparition incloses so much of the northern ́or southern heavens as never goes out of our sight, day or night, when we live altogether at the same place. To find this circle, élevate, the celestial pole to the latitude of the given place: then take a pencil, place it where that latitude on any meridian intersects the horizon, and turn the globe; the circle it makes incloses the stars of perpetual apparition.

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Example. How much of the heavens never go out of sight of the people of London ??

Can the people of Jamaica see any part of the great Bear?

How far must, I travel south before I can see the Crusero, or Cross?

Travelling south, where shall I lose sight of the North Polar Star?

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