Geodaesia : or, The art of surveying and measuring land made easy (1768)
Love, John, fl. 1688, Clark, Samuel · London : Printed for J. Rivington · leaf 204
juft upon 90 deg. (infome femicircles there is a line on the back-fide ofthe brafs limb, on purpofe for the fetting it hori-zontal.) Then (firil fere wing the inftrument fafl)move the index up and down, till through thefights you efpy the top of the tower at A ; fee thenwhat degree upon the limb is… … yards; then have you all the angles known, (admit-ting the angle the tower makes with the ground,viz. d to be a right angle) and the bafe to find theperpendicular A B; which you may do, by Cafe I.£>f Trigonometry j thus, N As 182 Heights and Diftances. As the fine of the angle A at 32 9,724210…
Surveying
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