Nine geometricall exercises, for young sea-men and others that are studious in mathematicall practices: containing IX particular treatises, whose contents follow in the next pages. All which exercises are geometrically performed, by a line of chords and equal parts, by waies not usually known or practised. Unto which the analogies or proportions are added, whereby they may be applied to the chiliads of logarithms, and canons of artificiall sines and tangents. By William Leybourn, philomath.

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Title

Author

Leybourn, William, 1626-1716.

Publication

London :: printed by James Flesher, for George Sawbridge, living upon Clerken-well-green,

anno Dom. 1669.

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Link to this Item

http://name.umdl.umich.edu/A48344.0001.001

Cite this Item

"Nine geometricall exercises, for young sea-men and others that are studious in mathematicall practices: containing IX particular treatises, whose contents follow in the next pages. All which exercises are geometrically performed, by a line of chords and equal parts, by waies not usually known or practised. Unto which the analogies or proportions are added, whereby they may be applied to the chiliads of logarithms, and canons of artificiall sines and tangents. By William Leybourn, philomath." In the digital collection Early English Books Online 2. https://name.umdl.umich.edu/A48344.0001.001. University of Michigan Library Digital Collections. Accessed June 16, 2024.

Pages

The Analogie or Proportion.

As the Difference of Latitude is to the Radius;

So is the Tangent of the Rhumb from the Meridian to the Difference of Longitude:

And

As the Sine of the Rhumb is to the Difference of Longitude;

So is the Radius to the Distance run.

So the Latitude of the Place from whence you came being 52 degr. and the Longitude 35 degr. and the Rhumb upon which you sailed the third from the Meridian N. E. by N. 33 degr. 45 min. you shall find the Distance run to be 96 Leagues 2/10, and the Difference of Longitude 2 degr. 40 min.