CONTENTS. A Table of Logarithmic Sines, Tangents, Secants, and Verfed Sines, to every Degree and Minute of the A Table of Logarithmic Sines, Tangents, and Secants, for every Point, half Point, and Quarter Point of the Mariners Compass, 118 To find the Sine and Co-fine of an Arch, To find the Tangent and Co-tangent of an Arch, Ta To find the Solidity of a Wedge, To find the Superficies of a Sphere, To find the Solidity of a Sphere, To find the Superficies of any Zone, To find the Solidity of the Segment of a Sphere, To find the Solidity of the middle Zone of a Sphere, To find the Area of a circular Spindle, GEOMETRICAL DEFINITIONS. i. A POINT is that which has no parts, neither length, breadth, nor thickness. 2. A line is length, without breadth or thickness. 3. A surface, or fuperficies, is that which has length and breadth, without thickness. 4. A folid is that which has length, breadth, and thickness. 5. Points are the extremities of a line. 6. Lines are the boundaries of a fuperficies. 7. Superficies are the boundaries of a folid. 8. A ftraight line lies evenly between its extreme points. See plate 1. fig. 1. 9. Parallel lines are fuch as are in the fame plane, and keep the fame distance, though produced ever fo far. 10. An angle is the inclination of two lines of different directions, and meeting in a point. See plate 1. fig. 2. N. B. When two lines, AB, and BC, meet in any point, 11. When one straight line falls upon another ftraight line, fo as to make the adjacent angles equal to one another, each of them is a right angle and the ftraight line which falls upon the other is perpendicular to it. See plate 1. fig. 3. 12. An angle which is lefs than a right angie, is called an acute angle. See plate 1. fig. 4. |