1 Rev. 2 mins. & 1 Fixed. Rev. twice White, once Red 1 Rev. 3 mins.

1 Intermittent Bright 20 secs., dark 4.

1 Rev. 1 min.

1 Fixed.

1 Fl. 15 secs.

WEST COASTS OF ENGLAND, WALES, AND SCOTLAND.

West Coasts of England, Wales, and Scotland-Continued.

The Leading Lights are taken from "The Admiralty List of Lights in the British Islands, 1872." Candidates for all Certificates, for Second Mates', have to know the Leading Lights of one channel.

DEFINITIONS

IN

NAVIGATION AND ASTRONOMY.

The Candidate at his first Examination is to write a short definition against so many of the following terms as may be marked by the Examiner. The writing should be clear, and the spelling should not be disregarded.

1. The Equator.

The great circle on the earth, every point of which is the same distance from both poles.

2. The Poles.

The ends of the axis of the earth.

3. A Meridian.

A great circle passing through the poles.

4. The Ecliptic.

The circle which the sun appears to describe in the heavens. 5. The Tropics.

The parallels of latitude about 23° 28′ North and South of the equator.

6. Latitude.

The distance North or South of the equator.

7. Parallels of Latitude.

Small circles on the earth parallel to the equator.

8. Longitude.

The distance East or West of the first meridian, that is, from the meridian of Greenwich.

9. The Visible Horizon.

The circle where the sea and sky appear to meet.

10. The Sensible Horizon.

The plane touching the earth where the observer stands, and extending to the heavens.

11. The Rational Horizon.

The plane passing through the centre of the earth parallel to the sensible horizon.

12. Artificial Horizon and its use.

A reflector, whose surface is perfectly level, used for observing altitudes.

13. True Course of a ship.

The angle between the ship's track and the true meridian. 14. Magnetic Course.

The angle between the ship's track and the magnetic meridian.

15. Compass Course.

The track of the ship as shown by the compass.

16. Variation of the Compass.

The angle between the true and magnetic meridians.

17. Deviation of the Compass.

The deflection of the compass needle to the right or left of the magnetic meridian.

18. The Error of the Compass.

The deflection of the compass needle to the right or left of the true meridian.

19. Lee Way.

The angle between the ship's fore and aft line, and her track through the water.

20. Meridian Altitude of a Celestial Object.

The altitude when the object is on the meridian.

21. Azimuth.

The angle at the zenith between the meridian of the observer and the vertical circle passing through the object.

22. Amplitude.

The distance of the object from the East point when rising; but, from the West point when setting.

23. Declination.

The distance of an object North or South of the heavenly equator.

24. Polar Distance.

The distance of an object from the pole of the observer. 25. Right Ascension.

The angle at the pole between the meridian passing through the object, and the meridian passing through the first point of Aries.

26. Dip or Depression of the Horizon.

The depression of the visible horizon below the level of the sensible horizon.

27. Refraction.

The difference between the true and apparent places of an object caused by the bending of the rays of light as they pass through the earth's atmosphere.

28. Parallax.

A correction to apply to the altitude of an object to find what it would be if observed from the centre of the earth.

29. Semidiameter.

A correction to apply to the altitude of the limb of an object to find the altitude of its centre.

30. Augmentation of Moon's Semidiameter.

The difference between the Semidiameter as observed in the horizon and when in altitude.

31. Observed Altitude.

The height of an object above the visible horizon as observed with an instrument.

32. Apparent Altitude.

The height of an object above the sensible horizon.