Answer. The change in the direction of the wind would be the reverse of that given in Question 2 if the ship and the storm are travelling in the same direction, but the ship going faster than the storm. The change would also be the reverse if the ship were on the other side of the line of progression, but not going faster than the storm.

4 and 5. The questions and answers same as in Paper I.

6. Describe the track usually taken by cyclones in the Indian Ocean, near Mauritius, and state the seasons of the year in which they most frequently occur in that region. Answer.-In that region storms mostly travel towards the S.W.-ward. The season is from December to April, February and March being the worst months.

PAPER V.

1. The direction of the wind in a cyclone being East, state the probable bearing of its centre from the ship in the Southern Hemisphere.

Answer.-In the Southern Hemisphere the centre bears Eight points to the left of the direction of the wind; therefore, the centre bears about North.

2. And suppose that the wind during the passage of the same cyclone was found to change toward the N.E., what would be the ship's position with reference to the line of progression of the centre of the cyclone, and what action would you take?

Answer.-Wind backing from E. to N.E., the ship is on the left-hand side of the storm. I would carry sail with the wind on the port side until in a safe position, and then, if Fig. 121.

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necessary, heave-to on the port tack. If the barometer should again fall sail her, if possible, further out.

NOTE.-Ship in latitude 24° S., longitude 66° E. (near Mauritius, see Question 6) experiences a wind from the East, which hauls to N.E., or with the sun, with a falling barometer. This ship is in the left-hand semicircle of the storm, the centre bearing North and N.W., Eight points from the wind, also reckoned with the sun, and the storm is moving towards the S.W. (see Fig. 121). Now calling the top of your paper the North, sketch a small diagram as in margin above (Fig. 120) with a long arrow to show the direction in which the storm is moving. It will at once be evident that the ship's position is in the southern verge of the storm, in the "dangerous quadrant." To run in such a case would be to cross the advancing front; hence, by the answer just given she has headed away S.E. from the storm's track.

3.

E

Under what conditions would the change in the direction of the wind in the cyclone be the reverse of the above?

Answer.-See answer to same question, Paper I.

4 and 5. The same questions and answers as in Paper I.

6. Describe the track usually takon by cyclones in the Indian Ocean near Mauritius, and state the seasons of the year in which they most frequently occur in that region.

Answer.-In that region storms mostly travel towards the S.W.-ward. The season is from December to April, February and March being the worst months.

PAPER VI.

1. The direction of the wind in a cyclone being S.S.E., state the probable bearing of its centre from the ship in the Northern Hemisphere.

Answer.-About W.S.W. (in N. Hemisphere eight points to right).

2. And suppose that the wind during the passage of the same cyclone was found to change towards the S.S.W., what would be the ship's position with reference to the line of progression of the centre of the cyclone, and what action would you take?

Fig. 122.

Answer.-The wind veering to the right the ship would be in the right-hand semicircle of storm. Run the vessel with the wind on the starboard quarter, and when the barometer rises, if necessary, to keep the ship from going too far from her proper course, heave-to on the starboard tack. Should the barometer again fall, run her, as before, further out.

NOTE.-Referring to Question 6 the locality is seen to be the Bay of Bengal, where the average track is N.N.W., but change of wind shows storm going North, diagram (Fig. 122) shows ship as almost out of the dangerous quadrant. By sailing as above (see answer to question) the weather will be found to improve, and perhaps a fair wind may be got. It will be necessary, however, to watch the storm does not recurve to N.E.

3, 4, and 5. The questions and answers same as in Paper I.

6. Describe the track usually taken by cyclones in the Bay of Bengal, and state the season of the year in which they most frequently occur in that region.

Answer.-Those which originate in the north part of the bay usually progress towards N. by W. and N.W. by W. Those which originate near the Andaman Islands (not in the Andaman Sea) progress towards N.N.W. and West; whilst those that occur in the south part of the bay have usually a progressive motion towards the West, or a little North of West. The seasons are at the change of the Monsoons, April, May, September, October, also in November; the two latter being the worst months.

PAPER VII.

1. The direction of the wind in a cyclone being West, state the probable bearing of the centre from the ship in the Northern Hemisphere.

Answer.-About North (N. Hemisphere eight points to right).

2. And suppose that the wind during the passage of the same cyclone was found to change towards the S.W., what would be the ship's position with reference to the line of progression of the centre of the cyclone, and what action would you take?

Fig. 123.

Answer. The ship would be in the left-hand side of the line of progression of the centre of the cyclone. I would run the ship, keeping the wind, if possible, on the starboard quarter; and when the barometer rises, if necessary, to keep the ship from going too far from her proper course, heave-to on the port tack.

NOTE. According to Question 6 the locality is the China Sea, and the sketch in margin shows that the ship is in the S.E. part of typhoon, and in a hinder quadrant. To avoid the terrible sea of the wake the ship should be kept well out to the S.E.

3, 4, and 5. The questions and answers same as in Paper I.

6. Describe the track usually taken by cyclones in the China Sea, and state the seasons of the year in which they most frequently occur in that region.

Answer. In this region storms generally travel Westerly to North-Westerly in July and August, and South-Westerly to North-Westerly in the months of September, October, and November,

ORDINARY EXAMINATION.

EXAMINATION PAPER-No. I.

To be used by all Candidates when appearing for Examination for the first time only. DEFINITIONS.

The Candidate is requested to write at least ten of the following definitions. The writing should be clear, and the spelling not be disregarded.

I. THE EQUATOR is a great circle passing round the earth at an equal distance from each pole (see page 63, and Fig. 11, page 66).

2. THE POLES of the earth are the two extremities of its axis, about which it revolves (see Fig. 11, page 66).

3. A MERIDIAN is a great circle passing through the poles perpendicular to the equator (see page 65, also Fig. 11, page 66).

4. THE ECLYPTIC is a great circle representing the apparent annual path of the sun in the heavens (see page 157).

5. THE TROPICS are two small circles parallel to the equator, one of which is 23° 28′ north of it, and is called the Tropic of Cancer; the other is 23° 28′ south of it, and is called the Tropic of Capricorn.

6. LATITUDE is an are of a meridian intercepted between the place and the equator, and is reckoned in degrees (°), minutes ('), and seconds ("). (See page 65, also Fig. 11, page 66) 7. PARALLELS OF LATITUDE are small circles parallel to the equator (see page 65, also Fig. 11, page 66).

8. LONGITUDE is an arc of the equator intercepted between the "first meridian" and the meridian of the place (see page 65, also Fig. 11, page 66).

9.

THE VISIBLE HORIZON is the circle bounding the spectator's view at sea (see page 164). 10. THE SENSIBLE HORIZON is a plane, to which a plumb line is perpendicular, passing through the eye of the observer.

II. THE RATIONAL HORIZON is the great circle in which the plane drawn through the centre of the earth parallel to the sensible horizon meets the celestial concave.

12. ARTIFICIAL HORIZON.-A reflector, whose surface is perfectly horizontal, used to observe altitudes on shore.

13. TRUE COURSE OF A SHIP is the angle which a ship's track makes with a true meridian (see page 75, also Fig. 17, page 76).

14. MAGNETIC COURSE is the angle which a ship's track makes with the magnetic meridian (see page 75, and Fig. 17, page 76).

15. COMPASS COURSE is the angle which a ship's track makes with the compass needle (see page 75, also Fig. 17, page 76).

16. VARIATION OF THE COMPASS is the angle between the meridian of the place and the magnetic meridian (see page 75, also Fig. 17, page 76).

17. DEVIATION OF THE COMPASS.-The angle between the magnetic meridian and the direction of the compass needle, and represents the effect of disturbing forces of iron near it (see page 75, also Fig. 17, page 76).

18. THE ERROR OF THE COMPASS is the angle between the meridian of the place and the direction of the compass needle (see page 75, also Fig. 17, page 76).

19. LEEWAY is the angle which a ship's track makes with her fore-and-aft line, or keel (see page 75, also Fig. 17, page 76).

20.

MERIDIAN ALTITUDE OF A CELESTIAL OBJECT is the angular height of the object above the horizon when it is on the place of observation,

21. THE AZIMuth, or True BEARING of a heavenly body, is the arc of the horizon between the N. and S. points and a vertical circle passing through the body (see page 163, also Fig. 45, page 172, and Fig. 48, page 174).

22.

THE AMPLITUDE of a heavenly body is the arc of the horizon between the East point and the centre of the object when rising, or the West point when setting (see page 164, also Fig. 45, page 172, and Fig. 48, page 174).

23. DECLINATION of a celestial object is the arc of a circle of declination between the object and the equinoctial (see page 159, and Figs. 45 and 48, pages 172 and 174).

24. POLAR DISTANCE is the arc of a circle of declination between the elevated pole and the object (see page 161, also Fig. 45, page 172, and Fig. 48, page 174).

25. RIGHT ASCENSION of a celestial body is an arc of the equinoctial, or an angle at the pole, between the first point of Aries and the meridian passing through the object (see page 159, and Fig. 48, page 174).

26. DIP is the angle through which the sea horizon is depressed in consequence of the elevation of the spectator above the surface of the earth. It is the angle at the eye of the observer between the visible and sensible horizons (see Fig. 40, page 164).

27. REFRACTION is a correction to be applied to the place of a heavenly body on account of the effect of the earth's atmosphere, which bends the rays of light passing through it into a position more nearly vertical, and thus causes the apparent places of the heavenly bodies to be above the true places (see page 164).

28. PARALLAX is the angle subtended at the object by that radius of the earth which is drawn to the place of observation.

NOTE.-Parallax is a correction to be added to the apparent altitude, or that which is taken on the earth's surface, to make it what it would have been if observed at its centre and estimated from the rational horizon (see page 164).

29. SEMIDIAMETER of a heavenly body is the angle subtended at the eye of the observer by the radius of the disc (see page 165).

30. AUGMENTATION OF THE MOON'S SEMIDIAMETER is the apparent increase of the Moon's semidiameter arising from the decreased distance from the Moon as her altitude increases (see page 166).

31. OBSERVED ALTITUDE of a heavenly body is its angular distance from the sea horizon read from the arc of the instrument by which the altitude has been measured.

32. APPARENT ALTITUDE.-When the observed altitude has been corrected for Dip and Semidiameter (if any) the result is the apparent altitude, that is, the apparent angular height of the object's centre above the sensible horizon (see page 168).

33. TRUE ALTITUDE.-When the Apparent Altitude has been corrected for Refraction and Parallax (if any) the result is called the True Altitude, that is, the true angular distance of an object's centre above the Rational Horizon (see page 166).

34. ZENITH DISTANCE is the arc of a vertical circle intercepted between the zenith and the place of the body (see page 163, also Fig. 45, page 172, also Fig. 48, page 174).

35. VERTICAL CIRCLES are great circles passing through the zenith perpendicular to the horizon.

NOTH.-They are also called Circles of Altitude, because altitudes are measured on them, and Circles of Azimuth, as marking out all points that have the same azimuth (see page 163). 36. PRIME VERTICAL is the vertical circle passing through the East and West points of the horizon (see page 163, also Fig. 45, page 172, also Fig. 48, page 174).

37. CIVIL TIME is the time used in ordinary life to record events. It begins at midnight and ends at the following midnight, and its hours are reckoned through twice 12; from midnight to noon, denoted by A.M., and then from noon to midnight, denoted by P.M. (see page 175).

38. ASTRONOMICAL TIME is the time used in all astronomical calculations; it begins at noon and ends at the following noon, its hours being reckoned from oh to 24h (see page 175).

39. SIDEREAL TIME is the angle at the pole of the heavens between the celestial meridian and an hour circle (or circle of declination) passing through the first point of Aries, measuring from the meridian westward (see page 169).

40. MEAN TIME is the angle at the pole between the celestial meridian and a circle of declination passing through the mean sun, measuring from the meridian westward.

41. APPARENT TIME is the angle at the pole between the celestial meridian and an hour circle (or circle of declination) passing through the place of the sun's centre, measuring from the meridian westward (see page 167).

42. EQUATION OF TIME is an angle at the pole, or the corresponding arc of the Equinoctial intercepted between the hour circles passing through the places of the true and mean sun. It is the difference between apparent and mean time (see hour circles, page 166, also page 168).

43. HOUR-ANGLE of a celestial object is the angle at the elevated pole, or the corresponding arc of the Equinoctial intercepted between the celestial meridian and the hour circle passing through the place of the body.

44. COMPLEMENT OF AN ARC OR ANGLE is the remainder obtained by subtracting the arc or angle from 90° (see page 39).

45. SUPPLEMENT OF AN ARC OR ANGLE is the remainder obtained by subtracting the aro or angle from 180°.

FOR SECOND MATE.

1. Multiply 7654 by 95, and 723°36 by 875°52, by common logarithms.

2. Divide 3654000 by 7308, and 174.6015 by 58.2005, by common logarithms.

Correct the courses for deviation, variation, and leeway, and find the course and distance from the given point, and the latitude and longitude in by inspection.

4.

1887, January 1st, in long., 102° 41 W., the observed mer. alt. of the sun's L.L. was 59° 59′ 50°, bearing South, index error +50", height of eye 15 feet: required the latitude. 5. In latitude 37° the departure made good was 89.2 miles: required the diff, of long. by Parallel Sailing.