## Elements of Surveying: With a Description of the Instruments and the Necessary Tables, Including a Table of Natural Sines |

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Page 12 - FRACTION is a negative number, and is one more than the number of ciphers between the decimal point and the first significant Jigure.

Page 49 - ... the square of the hypothenuse is equal to the sum of the squares of the other two sides.

Page 34 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds.

Page 19 - Two lines are said to be parallel, when being situated in the same plane, they cannot meet, how far soever, either way, — both of them be produced 13. A plane figure is a plane terminated on all sides by lines, either straight or curved. If the lines are straight, the space they enclose is called a rectilineal figure, or polygon, and the lines themselves, taken together, form the contour, or perimeter of the polygon. 14. The polygon of three sides, the simplest of all, is called a triangle; that...

Page 35 - The secant of an arc is the line drawn from the centre of the circle through one extremity of the arc, and limited by the tangent passing through the other extremity. Thus, OC is the secant of the arc AB.

Page 128 - Let this board be so fixed to a vertical staff" as to slide up and down freely ; and let a small piece of board, about three inches square, be nailed to the lower edge of it, for the purpose of holding a candle. About twenty-five minutes before the time of the greatest eastern or western elongation of the pole-star, as shown by the tables of elongations, let the theodolite be placed at a convenient point and leveled.

Page 112 - Then, the difference between the sum of the northings and the sum of the southings will be...

Page 128 - ... the east, and the reverse when the elongation is west. At the time the star attains its greatest elongation, it will appear to coincide with the vertical spider's line for some time, and then leave it, in the direction contrary to its former motion. As the star moves...

Page 21 - AXIOM is a self-evident truth ; such as, — 1. Things which are equal to the same thing, are equal to each other. 2. If equals be added to equals, the sums will be equal. 3. If equals be taken from equals, the remainders will be equal. 4. If equals be added to unequals, the sums will be unequal. 5. If equals be taken from unequals, the remainders will be unequal. 6.

Page 127 - Take a board, of about one foot square, paste white paper upon it, and perforate it through the centre ; the diameter of the hole being somewhat larger than the diameter of the telescope of the theodolite. Let this board be so fixed to a vertical staff, as to slide up and down freely : and let a small piece of board, about three inches square, be nailed to the lower edge of it, for the purpose of holding a candle.