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.

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    170. Problemes of Sayling abouts, though by. my feckoning, well reGtified by obfervations, i | find my:felf co be (till fhort.of the Lizard, about 317 leagues : yet I follow not the great Circle any further, “but that I may the more cere cainly fall wich the place intended, whether Sedy or the Lizard,| keep my felfin that parallelvAnd the rather,becaufe the reckonings outward and‘homeward, of voyages made to.this and other placesof the Wef# dies; do for the molt, part difagree much. Which difagreementari- fetch: pattly by the currant fetting homeward from thete parts $ but chiefly becaule thofe reckonings are kept upon the plain or common Sea-Chart; which Chart, except a man return the fame way home that he wentout, is commonly fubject to gcofle errours. Andawhereas bknow; that chemoft part are wholly addicted to the ufe of this Chart sifome alfoidefpiling all others, and may haply be of- fended that 1 fhould thus tax it with groffe errours; I thal] make it ap- pear(partly in chis prefene example that I do it not’ without jult caufe. In faslitig from the Lizard tothefe Lands, and fo toother parts of the Welt Indiess!:mem: commonly, tun far to the fouthwards, as fometimes into: the latitude of! 39 degrecs ,.. fometimes more foucherly,. to. get a wirid;; bur: coming, homewards, their couifes are commonly more northerly than. the Rumb. leading from thence home, But-in this example following, let us) keep a, means, and to make Shorty {uppote a man fhould: fail.from. the Lizard {outh welt neer 500 leagues, and then find himfelf tn the latitude’ of 32 de- orees:20 minutes, and from thence well 782 leagues, til he find him- felfdireétly fouth from Sammers Iflands, and about two leagues off. Then by this reckoning on the plain Chart, Summers Tjlands {hould be diltant from the Lizard 1199. leagues ina {traighe courfe, Now admitiing this reckoning outward bound to be tue, and thee places.to. be thus ficuated on the common Chart; let us {uppote the reckoning homewards to be alfo kept on the fame Chart. And becaufe coming home: men keep to the noithwards, let us fuppofe that he (teers away. #e half a point ealterly 200 leagues then #6 by ¢ 100 leagues; ¢ we half apoint northerly 165 leagues, e”¢ 130 leagues; ealt north ealt -halfea point ealterly 88 leagues;,caft and by noith 70 leagues ;. and-e.307- leagues. Then by, this. reckoning, upon ane plain. Chart.:» he fhould: be fhort of the Lizard about 160 leagues.