Four separate Days Work, 181 185 The Method of finding the Latitude by two Altitudes, 90 find the Latitude by the Meridian Altitude of the Moon, 213 To find the Apparent Time, and thereby regulate the going of Of finding the Longitude at Sen, To reduce the observed Distance to the true To find the Sun's true Altitude by Calculation, To find the Longitude by the Eclipses of Jupiter's Satellites, 248 The Manner of surveying Sea Coasts and Harbours, To find the Height and Distances of Objets at Sea, 256 Atable for finding the Distance of TerrestrialObjects at Sea, 260 An Explanation of the Sea Terms, The Examination of a Young Sea Officer, respecting the work- ing of a Ship at Sea, and conducting her into the different 1 The Tables stand in the following Order. TAB. I. The Difference of Latitude and Departure for Points TAB. III. The Meridional Parts Tab. IV. The Latitude and Longitude of Places Tab. V. The Refraclion of the heavenly Bodies in Altitude TAB. VI. The Dip of the Horizon TAB, VII. The Sun's Parallax in Altitude Tab. VIII. The Augmentation of the Moon's Semi-diameter Tab. IX. The Dip of the Sea at different Distances from the TAB. XI. The Variation of the Sun's Declination TAB. XII. The Sun's Right Ascension TAB. XV. Shewing the Time of ihe Sun, Moon, and Star's Setting when they have North Declination, and the Time of their Rising when they have South Declination TAB. XVI. For finding the Latitude by two Altitudes of the Sun TAB. XVIII. For turning Degrees and Minutes, into Time Tab. XIX. The Proportional Logarithms Distance from the Sun or fixed Stars TAB. XXII. Of artificial Sines, Tangents, and Secants. E R R Α Τ Α. Page 111, In the second Line under the Table, reject 55 Miles of Page 109, In the Answer to the seventh Question, for as Diff. of Lat. 786, read Diff. of Long. Page 139. In finding the Number of the Month, for 7 read 8. Page 200. The fifth Line from the Bottom, for Boards read Boats. Page 240, Question 6. Make the supposed Longitude 8o W. the re- duced Time sh. 22' 57", the true Time will be 4h. 38' 7", and the true Distance 77° 38' 27". Find the Distances between 3 and 6 Hours, and the Longitude will be 7° 59' & West. N. B. The rapid Sale this Book has had since its first Publication, has induced Persons in Scotland and other places to copy it, many of which THE PRACTICAL NAVIGATOR, AND SEAMAN's NEW DAILY ASSISTANT. G E O M E T R Y. DEFINITIONS. EOMETRY is that Science by which we compare such and Solids, whose original is from a Point. I. - A. not any Quantity, but only an affignable Place in a Quantity denoted by a Point, as at A. Such a Place may be conceived fo infinitely small, as to be void of Length, Breadth, and Thickness; and therefore a Point may • be said to have no Parts.' II. III. IV. А V. Lines V. Lines not parallel, but inclining towards each other, whether they are right Lines or circular, will, if they are extended, meet, and make an A Angle; the point where they meet is called the Angular Point, as at A; and according as such Lines stand nearer or farther off each other, the Angle is said to be greater or less, whether the Lines that include the Angle be long or short. All Angles included between Right Lines, are called Right-lined Angles, and fall under these three Denominations; viz. A Right Angle, an Obtufe Angle, and an Acute Angle. VI. D A Right Angle is that which is included between two Lines that meet each other perpendicular, as DC meets A B. C A VII. An Obtufe Angle is that which is greater than a Right Angle, such as the Angle included between the Lines A Cand C B. D Segment Chord Line IX. A Circle is a perfect round Figure ; the Point C in the Middle is the Centre, and is bounded by a round Line called its Circumference, or. Periphery. A Right Line, drawn from the Centre to the circumference, is called the Radius, or it is the Distance taken in the Compafles to describe a Circle, as A C. Dial meter Note. The Radius, generally used in describing Circles, is < 60°, (taken from the Line of Chords) the Circumference of which ( will contain 360°, the Number of equal Parts or Degrees that all « Circles are supposed to be divided into ; and each of these De grees are divided into 60 equal Parts, called Minutes, &c. • All Angles are measured by an Arch of this Circle, described upon the Angular Point as a Centre, with the Chord of 60°, as above, and the Angle is faid to be greater or less, according to the • Number of Degrees contained between the Legs; but the Sides or * Legs are measured by a Scale of equal Parts.' The Diameter is twice its Radius, joined into one Right Line drawn through the Centre, which divides the Circle into two equal Parts called Semi-circles. A Quadrant is half a Semi-circle. A Chord Line is a Right Line that cuts the Circle in two un. equal Parts called Segments. A Sector is a Figure included between two Radius's, and is less than a Quadrant. All Plan Triangles are Figures comprehended under three Right Lines, and are distinguished into three Sorts ; viz. A Right-angled Triangle, an Obtufe-angled Triangle, and an Acute-angled Triangle. X. C of its Legs perpendicular to the other, and is equal to a Quadrant or 90°; as B AC; the longest Side of which is called the Hypothenuse, as B C, and the other two Sides are called Legs. В. A XI. E An Obtuse-angled Triangle is that which hath one of its Angles greater than a Right Angle, as E DF. D XII. H An Acute-angled Triangle is that which hath all its Angles less than a Right Angle, G as G HI. |