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ELEMENTARY NAVIGATION

нов

YOUNG SEA MEN AND Y A OHTSMEN.

Navigation has been defined as the art of conducting in the sense of
piloting or guiding—a ship from one port to another; and this piloting on the
open ocean, far out of sight of beacons, landmarks and lighthouses, rests on the
determination of DIRECTION, DISTANCE, and RELATIVE Position,-combining
observation with calculations that are the practical application of Geometry
and Astronomy. It is the purpose of this little work to explain the use of
the instruments, and the kind of calculations, that are required in Navigation,
as well as the usual methods that are adopted from day to day during a voyage
to find what is called the Saip's PLACE AT ŞEa, which is the basis on which
rests the direction of her course towards the port of destination,

ARITHMETIC OF NAVIGATION.
The first thing to be considered is-Do you understand the Arithmetic of
Navigation ?-if you do not, it can be explained in a few pages, and these the
beginner would do well to carefully read; he who is proficient in this knowledge
can pass on to the next subject — Circles and Angles.”

It is of course taken for granted that you are well up in the four rules of
simple arithinetic-addition, subtraction, multiplication, and division—which
are as constantly required in Navigation as in daily business transactions. ·.

Let us begin with the arithmetic of the Circle and of Time, the parts of
which in both are divided sexagesimally, or, in other words, sixty of a less
denomination make one of a greater. Two short TABLES furnish us with the
basis of computation.

(A) DivisioNS OF THE CIRCLE, OR ANGULAR MEASURE.“
60 seconds “ . . . . make .... 1 minute

60 minutes . . . . . . . . . . l degree o
and these terms are respectively marked "" ", so that 5° 51' 28" is to be read
5 degrees, 51 minutes, 28 seconds.

(B) MEASUREMENT OF TIME.
60 seconds (s.). ... make . .... 1 minute (m.)

60 minutes. . . i ; , . . . . 1 hour (h.)
but in this instance the terms are respectively marked h. m. S., so that
6b. 31m, 248, is to be read 6 hours, 31 minutes, 24 seconds. . . .

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Arithmetic of Navigation ... ... ... ...

Relation of Circular Measure to Time

Circles and Angles ... ... ... ...

Protractor and Diagonal Scale ...

Ship's Place at Sea-Latitude and Longitude ...

Mariner's Compass ... ... ... ...

Variation of the Compass ...

Deviation of the Compass ...

Error of Compass ... ...

Leeway ... ... ...

Current-Set and Drift ...

...

Log-ship and Log-line

Sailings; a Traverse and the Traverse Tables ...

Latitude left and Latitude in

Departure ... ... ... ...

To convert Departure into Difference of Longitude

Longitude left and Longitude in .......

On taking a Departure-Cross Bearings

Day's Work ... ... ... ... ... ... ...

Ship’s Reckoning ... ... ... ... ... ...

Mercator's Chart ... ... ... ...

Examination in Chart (Board of Trade)

Signs and Abbreviations used on Charts

Lead-line ,... ... ... ... ... ... ...

Sextant and Quadrant ... ... ... ...

Adjustments of the Sextant (Examination Paper)

To Read the Sextant

Tides and Time of High Water ... ...

Magnetism of Iron Ships ... ...

Deviation of the Compass (Examination Paper)

Artificial Horizon ... ... ... ... ... ...

Course and Distance by Mercator's Sailing ... ...

Terms in Navigation and Nautical Astronomy (Examination Paper)

Latitude by Meridian Altitude ... ... ... ...

Longitude by Chronometer and Sun's Altitude... ...

Brief Rules in Navigation for the Yachting Certificate

... (Appendix)

International (Commercial) Code of Signals ... ...

(Appendix)

Seamanship ... ... ... ... ... ... ... ... ... (Appendix)

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PAGE.

Arithmetic of Navigation ... ...

Relation of Circular Measure to Time ...

Circles and Angles ... ...

Protractor and Diagonal Scale ...

Ship's Place at Sea — Latitude and Longitude

11

Mariner's Compass ... ... ....

Variation of the Compass ...

Deviation of the Compass .i.

Error of Compass ... ...

Leeway ... ... ...

Current-Set and Drift ...

Log-ship and Log-line

Sailings; a Traverse and the Traverse Tables ...

Latitude left and Latitude in ...

Departure ... ... ... ... ... ..

To convert Departure into Difference of Longitude

Longitude left and Longitude in .......

On taking a Departure-Cross Bearings

Day's Work ... ... ... ... ... ... ...

89

Ship’s Reckoning ... ... ... ... ... ...

Mercator's Chart ... ...

Examination in Chart (Board of Trade)

Signs and Abbreviations used on Charts

Lead-line ,... .. ... ... ... ... ...

53

Sextant and Quadrant ... ... ... ...

55

Adjustments of the Sextant (Examination Paper)

To Read the Sextant ... ... ... ... ...

Tides and Time of High Water ... ... ... ... ...

Magnetism of Iron Ships ... ... ...

Deviation of the Compass (Examination Paper)

Artificial Horizon ... ... ... ... ... ... ...

Course and Distance by Mercator's Sailing ... ... ...

Terms in Navigation and Nautical Astronomy (Examination Paper)

Latitude by Meridian Altitude ... ... ... ...

Longitude by Chronometer and Sun's Altitude... ..

Brief Rules in Navigation for the Yachting Certificate

(Appendix) 1,16

International (Commercial) Code of Signals ...

(Appendix) 1, 16

Seamanship ... ... ... ... ... ... ... ... ... (Appendix) 1, 12

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ELEMENTARY NAVIGATION

FOR

FOR

YOUNG SEAMEN AND Y A OHTSMEN.

Navigation has been defined as the art of conducting-in the sense of piloting or guiding—a ship from one port to another ; and this piloting on the open ocean, far out of sight of beacons, landmarks and lighthouses, rests on the determination of DIRECTION, DISTANCE, and Relative Position,—combining observation with calculations that are the practical application of Geometry and Astronomy. It is the purpose of this little work to explain the use of the instruments, and the kind of calculations, that are required in Navigation, as well as the usual methods that are adopted from day to day during a voyage: to find what is called the Ship’s PLACE AT ŞEA, which is the basis on which rests the direction of her course towards the port of destination.

ARITHMETIC OF NAVIGATION. THE first thing to be considered is-Do you understand the Arithmetic of Navigation ?-if you do not, it can be explained in a few pages, and these the. beginner would do well to carefully read; he who is proficient in this knowledge can pass on to the next subject" Circles and Angles.”

It is of course taken for granted that you are well up in the four rules of simple arithmetic-addition, subtraction, multiplication, and division—which are as constantly required in Navigation as in daily business transactions. :.

Let us begin with the arithmetic of the Circle and of Time, the parts of which in both are divided sexagesimally, or, in other words, sixty of a less denomination make one of a greater. Two short TABLEs furnish us with the basis of computation.

(A) DivisiONS OF THE CIRCLE, OR ANGULAR MEASURE.“
60 seconds (“). ... make . . . . 1 minute (
60 minutes . . . . .

. . . . l degree o and these terms are respectively marked o!", so that 5° 51' 28" is to be read 5 degrees, 51 minutes, 28 seconds.

(B) MEASUREMENT OF TIME..
60 seconds (s.). ... make, ... 1 minute (m.)

60 minutes,... i ; , . . . . 1 hour (h.) but in this instance the terms are respectively marked h. m. 8., so that 6b. 31m. 248, is to be read 6 hours, 31 minutes, 24 seconds. ; i .

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