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
Catalogue details

Licence: Public Domain Mark

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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    EEO ee lay one of the Hairs of the Sector to the Day of the. Month, and it cuts this 9th Circle in the Example, Fuly 4, I would know the Time of the Sun's rifing and fetting, the Length of the Day and Night, and how much the Days have decreas d, OpERATION. Lay the Hair of the Sector to the given Day, Yuly 4, and it cuts this oth Circle at 40” paft 4, the Sun’s rifing ; and 40” before 8, his fetting ; which doubled, is 15 58’ 40’, the Leneth of the Day ; this fubftracted from the longeft Day at Londou 165 25 28”, setts 26° 48”, and fo 10. The Defcription and Ufe of the Texth Cir~ cle, as mark d on the Seétor. This Circle gives you the Equation of natural Days, common] called the Equation of Vime, the Reafon of ahhich you have under that Word, | to which I refer you; it isnumbred round with Figures, which fignifies Minutes, and the Divi- fions are Seconds, every one of which is 13. There are four Days in the Year that the Sun and pendulum Clock go together, which are thefe, April 4 Fune 6 Auzuft 20 . rte 12 . with thefe Words, faft, flow, which tells you whether the Watch is fatter or flower than the Sun, — There
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