The description and use of an universal and perpetual mathematical instrument ... shewing the most expeditious and exact method of solving all practical questions in arithmetick, trigonometry, navigation, dyalling, astronomy, &c. ... / by Benjamin Scott.

Scott, Benjamin, -1755.

Date:: 1733

Credit: The description and use of an universal and perpetual mathematical instrument ... shewing the most expeditious and exact method of solving all practical questions in arithmetick, trigonometry, navigation, dyalling, astronomy, &c. ... / by Benjamin Scott. Source: Wellcome Collection.

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$“at i, ay F wie [3] Depreffion of the Pole, is fo many Degrees as you travel or fail towards the Equator from either Pole ; youare faid to deprefs the Pole £6 much, becaufe it feems lower to you or nearer to your Horizon. Degree, is the 360th Part of any Circle, or the 30th Part of a Sign, mark’d®. Digit, 1s the twelfth Part of the Sun or Moon’s Diameter. Dominical Letter, or Lord’s Day Letter, is one of the firft {even of the Alphabet, whereof _ every common Year has one, and every Leap- Year two, by which the Sundays are marked throughout the Year in Almanacks ; and 'T'ab.I. in the Inftrument fhows the dominical Letter for any Year by Infpection. Excliptick, is one of the fix great Circles of the Sphere, interfeting the Equinoétial in the two oppofite Points Aries and Libra, making anAngle therewith of 23° 4, called the Obliquity of the Ecliptick, equal to theSun’s greateft Decli- nation: In this Circle, according to Appearance, the Sun is always found ; it 1s divided into twelve equal Parts, called Signs, and every Sign into 30°, every Degree into 60’ and each Minute into 60”, &c. Always in or near this Line (Circle) are the Eclipfes of the Lumina- ties made, from whence it takes its Name: this Circle alfo interfects the two Tropicks of Cancer and Capricorn. : ae Elevation$