Copy 2

The description and use of ... Gunter's quadrant ... To which is added, the use of Nepiar's [sic] bones in multiplication, division, and extraction of roots ... / [William Leybourn].

  • William Leybourn
Date:
1731-1732
Catalogue details

Licence: Public Domain Mark

Credit: The description and use of ... Gunter's quadrant ... To which is added, the use of Nepiar's [sic] bones in multiplication, division, and extraction of roots ... / [William Leybourn]. Source: Wellcome Collection.

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    Hour of 12 in Summer, the Thread the Hour of 12 in Winter, the Thread will fall on the 6th of Fanuary and the 14th of November, and which of thefe is the Day of the Month requir’d, the Quarter of the Year will determine. % Bead by the Place of the Sun, and by the Day of the Month; but the beft Way is that by the Place of the Sun, for in the other fome fmal]l Difference may arife by the Leap-year, There is alfo.a third Way by a Table of the -Sun’s Declination for each Day of the Year, (which Seamen are feldom with- out) and if fo, tae Bead may be fet there- unto in the Line of Declination. 6; To know how high the Sun will be, at auy Hour of the Day given, through- out the Year. The Bead being reétify’d for the ‘Time, by any of the Ways aforefaid, bring it to the Hour given from the Flour of 12 towards the Line of Dechi- nation