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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    cso] and is always North, when the Sun is in northern ) Signs ; and South, when he is in fouthern. Example, What's the Sun’s Amplitude, Fuly) 3? OrERATION. Tay the Hair of the SeGtor to either the Day; of the Month in the rath Circle, or to the Sun’ss Place in the 5th Circle, and it will cut the: eighth Circle in 36°4, the Amplitude of rifing; and fetting trom the Eaftand Weft to the North-- ward, It 1s of great Ufe to Mariners to find the: Variation of the Compafs, 9. The Defcription and Ufe of the Ninth Cir=. cle, as mark d on the SeGor. This Circle fhews the Sun’s rifing and fet-- ting every Day in the Year, for the Latitude off 51°32” ; in which the Roman Letters ftand for: his rifing, and the common Figure the {etting 5; every Divifion of which Circle is a Minute ini Time, in which you may obferve the Sun rifes} on the roth of Fuse (being the longeft Day) at: 3° 47' 16, and fets that Night at 8 12’ 447 which are the Complement of each other tor 12 Hours ; the Double of the Sun’s fetting, al-. ways gives the Length of the Day; fo the longeft ' Day in Latitude of Zondom is 16 25’ 28, which: taken from 24 Hours leaves the Length of the: ‘Night, 7° 34’ 32”, See Page 17, the Words Ri-- fing and Satins. When you would find the: Sun's rifing and fetting for any Day propofed, , lay
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