Trigonometrie. Or, the doctrine of triangles: divided into two books. The first shewing the mensuration of right lined triangles: the second of spherical ... Both performed by that late and excellent invention of logarithms ... Whereunto is annexed (chiefly for the use of sea-men) a treatise of the application thereof in the three principal kinds of sailing. With exact tables of the suns declination ... and tables of the right ascension and declination of some eminent fixed stars ... Also other necessary tables used in navigation / [Richard Norwood].

  • Richard Norwood
Date:
1661
Catalogue details

Licence: Public Domain Mark

Credit: Trigonometrie. Or, the doctrine of triangles: divided into two books. The first shewing the mensuration of right lined triangles: the second of spherical ... Both performed by that late and excellent invention of logarithms ... Whereunto is annexed (chiefly for the use of sea-men) a treatise of the application thereof in the three principal kinds of sailing. With exact tables of the suns declination ... and tables of the right ascension and declination of some eminent fixed stars ... Also other necessary tables used in navigation / [Richard Norwood]. Source: Wellcome Collection.

    136/220 (page 120)
    eee ae ‘LT Egenomess tes: The five cit-C ABD, are ABe DB com, BDA. com. AD, com, oA. cular parts of shaded Mp sag ade A} the triangle.g GAD, arecom.AG.AGD. GDAs com, ‘AD, com. Az Where itis evident, G Band G:D: being quadiants G DB isa fight angle, and DB. isthe meafiire’ of the angle at‘Gs fo that the fide AB in the one is equal to compl. AG inthe other ; and the fide B-D in the one, equal to the angle AG D in the other, and ' compl. B DA inthe one isG DA. in the osher, aiid compl, A Din “conep’, A in the one, isthe fame with compl. 4 in the other, for the complement of the acute angle D 4 Bumtoa quadrant, is alfo the - compl, of the obtufe angle GAD. | LEMMA 4, Sf five circles of the {phere be foordered, that the firft tnter- | fed the fecond, the fecond the third, the third the fourth, the fourth the fifthyand the fifth, the firftyas right vy» angles: theright angled triangles made by their intér- ony feciconsydo all confift of the fame circular parts. “As in this Scheme, =. ee Wi a Let G reprefent the Z-~ mith, the north pole.and D the ‘Sdn being-in the). “Horizon. , Sothar- TG Be 1s an arch of the Meridi- -an of the place, BDF an a,ch of the : Horizon. FEC,an atch of che cir- ‘ele defcyibed about the fun C A Hy an arch of the “Meridian of the Sun. H.-L I, an arch of: the ‘Equinodtial. Then do thefe five are -Ches retein the conditi- | Ons required, le gi | @,: The firft incerfeCting the fecond in Bs the'fecond, the third in yr; eehattird, che fourth inC: the fourth, the fifth in H; and the fifth, che firtt in]. Andthele interfeAions at B,E,C, H, I, are at tight angles; Taste iil pal ft} nthe (nai fouith the lik The As) Land thearc are the andg The cireula pats mn then.’ aD, Wher the fa allorh kann