The geometrical square, with the use thereof in plain and spherical trigonometrie chiefly intended for the more easie finding of the hour and azimuth / by Samuel Foster ...

Title

The geometrical square, with the use thereof in plain and spherical trigonometrie chiefly intended for the more easie finding of the hour and azimuth / by Samuel Foster ...

Author

Foster, Samuel, d. 1652.

Publication

London :: Printed by R. & W. Leybourn,

1659.

Rights/Permissions

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Subject terms

Geometry -- Early works to 1800.

Trigonometry -- Early works to 1800.

Link to this Item

https://name.umdl.umich.edu/A40032.0001.001 content_copy

Cite this Item

"The geometrical square, with the use thereof in plain and spherical trigonometrie chiefly intended for the more easie finding of the hour and azimuth / by Samuel Foster ..." In the digital collection Early English Books Online. https://name.umdl.umich.edu/A40032.0001.001. University of Michigan Library Digital Collections. Accessed May 15, 2025. content_copy

Contents

• title page
• A DESCRIPTION OF THE SQUARE.
• Of the use of the Square in General for the Solution of Spherical Triangles.
  • ¶By having the Legs and Base, to find the Vertical Angle.
    • This is the general manner of work for this Proposition, which may be illustrated by these particulars.
      • FIRST,
        • Another Example.
      • SECONDLY,
        • To Illustrate it by an Example.
  • In any Spherical Triangle whatsoever.
    • For Example.
  • In any Spherical Triangle, whatsoever.
    • This general may be illustrated in particular thus.
      • For an Example.
    • By the Hour of the Day given, with the Suns distance from the elevated Pole, and the complement of his altitude above the Horizon, to find his Azimuth.
  • In any Rectangled Spherical Triangle whatsoever.
    • In the first,
    • In the Second,
    • In the third
• Of the use of the Square, in Right-lined Triangles.
  • Examples in these kinds, And first of sines, and equal parts, or Numbers.
  • Examples of equal parts, and Tangents.
  • ¶By having an Angle and the two sides comprehending it, to find the other Angles.
  • Secondly, in any plain Triangle whatsoever.
  • ¶By having the three sides of a plain Triangle, to find the Angles.
• Of the use of the Square in Proportions of equal parts or Numbers only.
• Of the use of the Square in the observation of angles.