The art of dialling : performed geometrically ... arthmetically ... instrumentally ... (1700)
Leybourn, William, 1626-1716 · London : T. Braddyll · leaf 80
ix. Secondly',. Take 25 deg. the Plains declination, out of your Line of Chords, and let that Diftance from D to a, and from E to b. Thirdly , A Ruler laid from W to a, will give Z the Ze- mith of the place 5 and a Ruler laid from W to />, will give S the South point of the Horizon ; both which… … Fourthly Becaufe the Pole of the World is always dr Kant from the Zenith, the Complement of the Latitude of . . ~ ■ ' . - ' t|l§
