PROP. IX. How by the Semicircle, to take the Plot of a great Champain-Plain, Wood, or other overgrown Ground, by measuring round about the same, and making Observation at every Angle thereof.
Admit A, B, C, D, be the figure of a Large overgrown Champain-Field; whose Plot is requi∣red. First Place your Instrument at A, laying the Index on the Diameter; and turn it about, untill you espy the Angle at D, and there fix it fast: and direct your sights to B, and note the Degree cut by your Index, in your Field-book, (as afore is taught) then remove your Instru∣ment to B, and there make the like observation, and so to C, and D, noting it down in your Field-book, as asore. Then with your Chain, measure the Sides AB, BC, CD, and DA, whose* 1.1 length note down in your Field book, and so you have finished and your work standeth thus.