The semicircle on a sector in two books. Containing the description of a general and portable instrument; whereby most problems (reducible to instrumental practice) in astronomy, trigonometry, arithmetick, geometry, geography, topography, navigation, dyalling, &c. are speedily and exactly resolved. By J. T.

About this Item

Title
The semicircle on a sector in two books. Containing the description of a general and portable instrument; whereby most problems (reducible to instrumental practice) in astronomy, trigonometry, arithmetick, geometry, geography, topography, navigation, dyalling, &c. are speedily and exactly resolved. By J. T.
Author
Taylor, John, 1666 or 7-1687.
Publication
London :: printed for William Tompson, bookseller at Harborough in Leicestershire,
1667.
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Subject terms
Mathematics -- Early works to 1800.
Navigation -- Early works to 1800.
Dialing -- Early works to 1800.
Link to this Item
http://name.umdl.umich.edu/A64223.0001.001
Cite this Item
"The semicircle on a sector in two books. Containing the description of a general and portable instrument; whereby most problems (reducible to instrumental practice) in astronomy, trigonometry, arithmetick, geometry, geography, topography, navigation, dyalling, &c. are speedily and exactly resolved. By J. T." In the digital collection Early English Books Online. https://name.umdl.umich.edu/A64223.0001.001. University of Michigan Library Digital Collections. Accessed May 13, 2025.

Pages

PROBL. 5.

To finde the Altitude of any Tree, Steeple, &c. at one station.

At any distance from the object (provi∣ded the ground be level) with your Instru∣ment, look to the top of the object along the outward ledge of the fixed piece, and take the angle of its altitude. This done, measure by feet or yards, the distance from your standing to the bottom of the object. Then say,

As the cosine of the altitude is to the measured distance numbred upon the lines of lines, so is the sine of the altitude to a fourth

Page 45

number of feet or yards (according to the measure you meeted the distance) to this fourth, adde the height of your eye from the ground, and that sum gives the number of feet or yards in the altitude.

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