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Then, on turning the globe, you will perceive that all the marks on the first quadrant of the ecliptic, that is, from Aries to Cancer, come sooner to the brass meridian than their corresponding marks on the equator. Now time, as measured by the dial, is represented by marks on the ecliptic ; that measured by a good clock, by those on the equator : hence, whilst the sun is in the first quarter of the ecliptic, the dial is faster than the clock.
On turning the globe, it will be found that the marks on the second quarter of the ecliptic, that is, from Cancer to Libra, come to the meridian later than those on the equator; and consequently the sun is slower than the clock. So it will be seen, that in the third quarter, from Libra to Capricorn, the sun is faster ; and in the fourth quarter, from Capricorn to Aries, slower than the clock.
The earth's motion in its orbit not being uniform, is another cause of difference between mean and apparent time. The equation of time is given for every day in White's Ephemeris, and in most almanacks. The days when the clock and sun agree, are April 15th, June 15th, Sept. Ist, and Dec. 24th. The days of greatest difference are Feb. Ilth, May 15th, July 26th, and Nov. 3rd.
QUESTIONS FOR EXAMINATION IN SECTIONS III. AND IV.
What is the literal signification of the word planet? How many planets are there, and in what order do they move round the sun ? How many are called inferior planets, and why are they so called ? Which of them are called superior planets, and why are they so called ? Which of them are called Asteroids ?
Are Mercury and Venus ever seen in the west in the morning, or in the east in the evening ? Which of the planets may be seen on the meridian at midnight?
How do the planets appear to move as seen from the earth? What is the greatest distance, in degrees, that Mercury and Venus ever appear from the sun ?
What is Mercury's mean distance from the sun ? What is its diameter? How long does it take to turn round the sun ? How long to turn on its own axis ? What are the distances, diameters, and periods of the other large planets ? How much greater is the heat of the sun at Mercury than upon our earth ?
How may the planet Venus be known in the heavens ? What appearance has it when viewed through a telescope ? At what rate does it move per hour? How much more light and heat do its inhabitants enjoy than we do? At what rate does the earth move per hour?
What is the name of that fluid which surrounds the earth? What are some of the benefits which we derive from it ?
What is the diameter of the moon, its distance from the earth, and the time of its revolution round the earth? What is the time between one new moon and another ? Explain the phases of the moon. How much more light does the earth afford to the moon, than the moon does to the earth?
How may Mars be known in the heavens?
How much less light does the sun afford to Jupiter than to us? How is this defect supplied ?
What appearance has Saturn in the heavens? How many moons has Saturn? In what respect does this planet differ from the others?
Which is the most remote planet yet discovered belonging to our system? How much light does the sun give to this planet? How many moons belong to it? What peculiarities have they?
What are the names of the four minor planets? When was Ceres discovered? Wherein do they differ from the other planets?
What are the parts of a comet? What is the usual form of the orbit of a comet? Name the most remarkable comets of modern times? What interesting fact has Encke's comet revealed ?
What is it that causes an eclipse of the moon ? Of the sun ?
Supposing the north pole to be inhabited, how long would the inhabitants uninterruptedly enjoy the light of the moon in winter ?
Within how many degrees of the nodes must the moon be, at the time of change, to produce an eclipse of the sun ? Within how many degrees, at full moon, to produce an eclipse of the moon ?
What is the greatest and least number of eclipses that can happen in any year, and how many of these must be of the sun ?
How may the moon's orbit be represented on the globe ? How may the moon's diurnal motion in the ecliptic be found?
How may the moon's longitude for any hour be found? How may the moon's place be found for any day and hour?
How may the moon's rising and setting be found? How may the moon's age be found? How is the moon's southing found?
How can it be found when the sun or moon is liable to be eclipsed ? Explain the phenomena of the harvest moon. How can the equation of time be explained by the globe ?
THE LATITUDES AND LONGITUDES
PLACES MENTIONED IN THE PROBLEMS.
Names of Places. Acapulco Adrianople Akerman Alaska (S. Pt.) Aleppo Alexandria Algiers Alicant Amsterdam Ancona Aracan Archangel Ascension (Is.) Astrakhan Athabasca (R.) Athens Ava Azof Azore (Is.) . Bagdad Barbadoes Barcelona Bastia Batavia Benares Bencoolen Bender Bergen Berlin Bermudas
Sea or Country. Latitude. Mexico
16° 50' N Turkey
41 45 N Turkey
46 12 N North America 55 ON Syria
36 11 N Egypt
31 13 N
36 48 N Spain
38 21 N Holland
52 22 N Italy
43 36 N Trans-Gangetic India 20 44 N Russia
64 34 N Atlantic Ocean
56 S Russia
46 30 N North America 57 ON Greece
37 58 N Birmah
21 51 N Russia
47 ON Atlantic Ocean 38 ON Turkey in Asia 33 25 N West Indies
13 5 N Spain
41 25 N Corsica
42 41 N Java
6 9 S India
25 20 N Sumatra
3 48 S Russia
46 45 N Norway
60 24 N. Prussia
52 31 N Atlantic Ocean 32 22 N
Names of Places. Berne Bhering's Island Bilboa Birmingham Bombay Borneo Boston Botany Bay Bordeaux Bremen Brest Bristol Buenos Ayres Brusa Cadiz Caen Cairo Calais Calcutta Calicut California Canary (Is.) Candia Canton C. Blanco C. Bojador C. Charles C. Charles C. Chudleigh C. Coast Castle C. Comorin C. Farewell C. Finisterre C. Good Hope C. Horn C. Matapan C. South C. St. Mary C. St. Roque C. Vela C. Verd
Sea or Country. Switzerland Pacific Ocean Spain England India Pacific Ocean United States New Holland France Germany France England South America Asia Minor Spain France Egypt France India Malabar, India North America Atlantic Ocean Candia Is. Mediter. China Africa Africa Labrador United States Labrador Guinea India Greenland Spain Africa South America Greece New Zealand Madagascar Brazil South America North Atlantic
Names of Places. Sea or Country. C. Wrath
Chinese Tartary Cayenne
French Guayana Charleston
United States Cherson
Norway Christmas (Is.) Pacific Churchill (Fort) Hudson's Bay Colombo
Ceylon Constantinople Turkey Cook's Strait
New Zealand Copenhagen
Denmark Coppermine R. mouth. North America Corinth
Prussia Darien (Isth.) America Delhi
South America Disco (Is. )
Davis's Straits Dover
Denmark Endeavour (R.) New Holland Falkland (Is.) Atlantic Ferro
Canaries Formosa (Is.)
Pacific Frankfort on Maine
Prussia Friendly (Is.) Pacific Geneva