able that these co-efficients should be disregarded or modified?-ART. 57. 25. The value of A, B, C, D, and E being given, or B, C, and D only, find the deviation on any required point of the compass, or construct a table of deviation, if required.-ARTS. 59, 60, 61, 62, 63, 64. 26. Describe how you would determine the deviation by means of a distant object, by reciprocal bearings, or by the figures on the dock walls.-ARTS. 46, 47, 48. 27. If it be required to determine the deviation of two or more compasses, it is most convenient to bring the ship's head, correct magnetic, on as many points as may be necessary. To determine the coefficients B, C, and D, the bearing of the ship's head by each compass is required. How would you for this purpose employ a Graphic Method ?— ART. 87. 28. State your rule for determining whether deviation is easterly or westerly.-ARTS. 46, 47. 29. Describe the use of the 'dumb-card,' or an azimuth card without a needle, in compensating a compass.-ART. 78. 30. If you determine the deviation by an azi、 muth or an amplitude of a heavenly body, it is then combined with variation,* which together is sometimes called the correction for the compass. State when the deviation is the difference between the variation and the correction, and when the sum; and when it is of the same name as that of the correction, and when of the contrary name.— ART. 49. The magnetic variation is best determined by a chart of the curves of equal magnetic variation. 31. In observing azimuths of heavenly bodies, the best method is by 'time azimuths,' since these can be observed without an altitude when the ship is in port, or the horizon cannot be defined from any cause. Given the sun's declination, the hour of the day, and the latitude, to find the true bearing of the sun.*-See Merrifield and Evers' 'Navigation and Nautical Astronomy.' 32. By night, if it be desirable to observe the correction of the compass. Given the day of the year, and time at ship, also the latitude of the place, to determine what* star will be in good position for this purpose.-See Merrifield and Evers' Navigation." 33. If your correcting magnets are so mounted that their positions can be altered, describe the process by which, on open sea, you can place the ship's head correct magnetic N. (or S.), and correct magnetic E. (or W.), and can make the correction perfect.-ART. 78. 34. Given the name of a star, the time, the place of ship, the variation of the compass, and the bearing of the star by compass. Determine the deviation, and name it east or west.-See Merrifield and Evers' Navigation.' 6 35. If an ordinary standard compass placed higher than the iron top sides be compensated whilst the ship is upright, what co-efficient will be affected by heeling ?-ARTS. 70, 71. * The process of finding time azimuths by the ordinary formulæ of spherical trigonometry is tedious, and since on board an iron ship these observations should be often repeated, the candidate will be allowed to use any table or graphic or linear method that will solve the problem within a half of a degree, the altitude of the heavenly body not being given. 36. When generally will this co-efficient be plus, and when minus ?—ARTS. 70, 71. 37. State the exceptions to this general rule.ART. 70. 38. Does the heeling error arise from the altered position of the sub-permanent poles of the ship, or from a change in the induced magnetism?— ART. 70. 39. To what extent is the heeling error altered by a change in the magnetic latitude of the ship? -ART. 80, 82. 40. If a ship is beating to windward; when she tacks, under what circumstances will the heeling error retain the same name, and under what circumstances will it take the contrary name ?— ART. 70. 41. If a ship is placed on the opposite tack by the change of wind, the ship's course being the same by compass, will the heeling error change its name ?-ART. 74. 42. Under what circumstances will the heeling error, if disregarded, take the ship to windward, or when to leeward ?-ART. 74. 43. Can the heeling error be compensated? If so, state the means to be employed.—ART. 82. 44. Can the compensation of the heeling error be depended on in every latitude? If not, state the reason.-ART. 82. 45. Given the heel, the direction of the ship's head by compass, and the heeling error observed, to find the approximate heeling error, with a greater or less given heel, and with the ship's head on some other named point of the compass, the ship's magnetic latitude being in both cases the same.-ART. 73. 46. Describe any instrument to show the ship's N heel (generally called a clinometer), and state how and where it should be fixed.-ART. 69. 47. Should the clinometer be observed when the ship is swung to determine the deviation when the ship is upright; if so, state the reason why.-ART. 71. |