A Treatise of Practical Surveying: Which is Demonstrated from Its First Principles. Wherein Every Thing that is Useful and Curious in that Art, is Fully Considered and Explained ... The Whole Illustrated with CopperplatesP. Wogan, 1795 - 319 páginas |
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Página 111
... Turn the Center A of the Quadrant next your Eye , and look along the Side AC , or 90 Side , to the Top and Bottom of the Object ; and noting down the Angles , measure the Dif tance from the Place of Obfervation to the Foot of the Object ...
... Turn the Center A of the Quadrant next your Eye , and look along the Side AC , or 90 Side , to the Top and Bottom of the Object ; and noting down the Angles , measure the Dif tance from the Place of Obfervation to the Foot of the Object ...
Página 147
... turn the Chain over to D , fo as to compleat a Parallelogram ; by reckoning off the fame Number of Links you had in BC , from E to D , and pulling each Part straight . + U 2 OF OF THE CIRCUMFERENTOR . T HIS Inftrument is compofed of Of ...
... turn the Chain over to D , fo as to compleat a Parallelogram ; by reckoning off the fame Number of Links you had in BC , from E to D , and pulling each Part straight . + U 2 OF OF THE CIRCUMFERENTOR . T HIS Inftrument is compofed of Of ...
Página 149
... turning the Box fo , that the Ends of the Needle may be equi- diftant from its Bottom , and it traverses or plays freely ) turn the Flower - de - Luce or North Part of the Box to your Eye , and looking through the fmall Aperture , turn ...
... turning the Box fo , that the Ends of the Needle may be equi- diftant from its Bottom , and it traverses or plays freely ) turn the Flower - de - Luce or North Part of the Box to your Eye , and looking through the fmall Aperture , turn ...
Página 151
... turn the South Part of the Box next your Eye , and having cut your Object at A , reckon the Degrees to the South Point of the Needle , which will be the fame as if they were taken from the Ob- ject to the Inftrument , the Direction of ...
... turn the South Part of the Box next your Eye , and having cut your Object at A , reckon the Degrees to the South Point of the Needle , which will be the fame as if they were taken from the Ob- ject to the Inftrument , the Direction of ...
Página 153
... turn the North of the Box to your Eye , and count your Degrees to the North Point of the Needle ; or you may turn the South of the Box to your Eye , and count your Degrees to the South End of the Needle . The Brafs Ring in the Box is ...
... turn the North of the Box to your Eye , and count your Degrees to the North Point of the Needle ; or you may turn the South of the Box to your Eye , and count your Degrees to the South End of the Needle . The Brafs Ring in the Box is ...
Términos y frases comunes
40 Perches ABCD Acres alfo alſo Anſwer Area Bafe Baſe Bearing becauſe bifect blank Line Cafe Center Chains and Links Chord Circle Circumferentor Co-fine Column confequently Cyphers Decimal defcribe Departure Divifion draw drawn Eaft eaſily Eaſt faid fame fecond Field-Book Figures fince firft Meridian firft Station firſt fmall Squares Four-Pole Chains ftationary Line fuch given half the Sum Inch Index infert Inftrument Interfection laft laid Latitude lefs Logarithm Mearing Meaſure Meridian Diſtance multiplied muſt Needle North obferve Off-fets oppofite parallel Parallelogram Perches Perpendicular Piece of Ground Plate Point Prob Protraction Protractor Quotient Radius refpective right Angles right Line Scale of equal SCHOLIUM Secant Sect Semicircle ſhall Side Sine South Square Root Sun's Survey taken Tangent thefe Theo Theodolite theſe thofe thoſe thro Trapezium Triangle ABC Trigonometry Two-Pole Chains uſed Variation Weft whofe
Pasajes populares
Página 13 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees; and each degree into 60 minutes, each minute into 60 seconds, and so on.
Página 88 - C' (89) (90) (91) (92) (93) 112. In any plane triangle, the sum of any two sides is to their difference as the tangent of half the sum of the opposite angles is to the tangent of half their difference.
Página 56 - ... logarithm of that number. EXAMPLE. • Required, the logarithm of 365. Answer, 2.56229. And though most tables of logarithms run but to 10000, yet by them the log. of any number not exceeding 10,000,000 may be found, and on the contrary, the number to any such logarithm, thus : 1 Find the log. of the first four figures of the given number 2. Take that log. from the log: of the number next following, and note their difference, 3. Multiply that difference by the remaining figures of the given number...
Página 91 - In the triangle ABC, there is given AB 240, the angle A 46° 30', and BC 200, to find the angle C, being acute, the angle B, and the side AC.
Página 89 - ED. that is as the sum of the two sides AB and BC, is to their difference ; so is the tangent of half the sum of the two unknown angles A and C, to the tangent of half their difference.
Página 32 - KCML, the sum of the two parallelograms or square BCMH ; therefore the sum of the squares on AB and AC is equal to the square on BC.
Página 19 - Four quantities are said to be in proportion when the product of the extremes is equal to that of the means, thus if A multiplied by D, be equal to B multiplied by C, then A is said to be to B as C is to D. POSTULATES OR PETITIONS. 1 . That a right line may be drawn from any one given point to another. 2. That a right line may be produced or continued at pleasure. 3. That from any centre and with any radius, the circumference of a circle may be described.
Página 13 - A chord is a right line drawn from one end of an arc or arch (that is, any part of the circumference of a circle) to the other ; and is the measure of the arc. Thus the right line HG, is the measure of the arc HBG.
Página 72 - ... these three proportions, for DE we put its equal be, for AE put ab, and for AD put ac, they will become AB : ab : : AC : ас, and AB : ab : : BC : be, and AC : ac : : BC : be.
Página 285 - Then if the true and magnetic amplitudes, be both north or both south, their difference is the variation ; but if one be north and the other south, their sum is the variation ; and to know whether it be easterly or westerly, suppose the observer looking...