PROBL. 7.
The declination and hour of the night, given to find the Suns depression under the horizon.
Lay the thread to the declination on the limb; but counted the contrary way, viz. from 60/0 on the movable piece toward the
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
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http://name.umdl.umich.edu/A64223.0001.001
- Cite this Item
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"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 April 27, 2025.
Pages
Page 15
head for Southern; and toward the end for Northern declination. This done take the nearest distance from the hour to the thread, and applying it to the line of altitudes, you have the degrees of the Suns depression. Ex. gr. at 5 deg. Northern declination, & 8 hours afternoon, the depression is 13 deg. 30 min.