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There are five Oceans, namely, the Northern, the Atlantic, the Pacific, the Indian, and the Southern. The Atlantic Ocean is usually divided into two Parts, one called the North Atlantic Ocean, and the other the South Atlantic, or Ethiopic Ocean. The Northern Ocean stretches to the Northward of Europe, Asia, and America, towards the North Pole. The Atlantic Ocean lies between the Continents of Europe and *ica, on the East, and America on the West. . That Part of the North Atlantic Ocean lying between Europe and America, is frequently called the Western Ocean. The Pacific Ocean, or, as it is sometimes called, the South Sea, is bounded by the Western and North-west Shores of America, and by the Eastern and North-east Shores of Asia. * The Indian Orean washes the Shores of the Eastern Coasts of Africa, and the South of Asia, and is bounded on the East by the Indian Islands and the Southern Continent.
The Southern Ocean extends to the Southward of Africa and Ame-
rica towards the South Pole. Note. Here the Teacher will perhaps find it convenient to have a Globe, or Map of the World before him, whereon he can point out the several Positions, Latitudes, Longitudes, &c. to the Pupil; as that will strengthen his Memory, and give him a better Idea than he can possibly have by only reading them over. The same may be observed in reading the Use of Gunter's Scale and the Quadrant.
N A v I G A T I o N.
HE great End and Business of Navigation is to instrućt the Mariner how to conduct a Ship through the wide and pathless Ocean, to the remotest Parts of the World, the safest and shortest Way, in Passages navigable. For the due and regular Performance of which are requisite— a perfeót Knowledge of the Figure and Motion of the Earth, the warious real, and imaginary Lines upon it, so as to be able to ascertain the real Distance and Situation of Places with respect to one another, with the Use of the several Instruments made Use of in measuring the Ship's Way, such as the Log, Half-minute Glass, Quadrant, to take the Altitude of the Sun and Stars; Compass, to represent the sensible Horizon ; and Azimuth Compass, to take the Azimuth or Amplitude of the Sun, in order to know the Variation of the magnetic Needle; Maps or Charts of the Seas and Lands together with the Depth of Water, and the Times and Settings of the Tides upon the Coasts he may have Occasion to approach near ; a competent Knowledge of Currents; of the Mould and Trim of the Ship, and the Sail she bears, that so due Allowance may be made for Leeway: By Help of these, and Skill in the Navigator, he may know at all Times the Place the Ship is in, which Way he must fteer, and how far, to gain his intended Port. " Notwithstanding what has been said, it may not be improper here to observe, that, As Latitude is counted from the Equator upon an Arch of the Meridian, North and South, the Difference of Latitude between two Places, both North or both South, is found by subtracting the less Latitude from the greater; but if one Latitude be North and the other South, the Difference is found by adding both Latitudes together. Consequently, if a Ship in North Latitude sails Northerly, or in South Latitude Southerly, she encreases her Latitude; but in North
she decreases her Latitude; because she sails nearer to the Equator, from whence the Latitude is reckoned. *
Wherefore in North Latitude sailing Northerly, or in South Latitude sailing Southerly, the Difference of Latitude added to the Latitude left, gives the Latitude in.
In North Latitude sailing Southerly, or in South Latitude sailing Northerly, the Difference of Latitude subtracted from the Latitude left, gives the Latitude in.
When the Latitude decreases, and the Difference of Latitude is greater than the Latitude sailed from, subtract the Latitude left from the Difference, and the Remainder will be the Latitude in, and of a different Name ; for it is plain, in this Case, that the Ship has cros
, ridian, or 180 Degrees, she changes her Longitude, or comes into a Longitude of a different Name.
What has been said, will be rendered familiar to the Learner by
the following Examples: