A Treatise of Mathematical Instruments, including most of the instruments employed in Drawing; for assisting the vision; in Surveying and Levelling, in practical Astronomy and for measuring the Angles of Crystals1864 |
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Page 24
... hypothenuse or axis a g will be parallel to the axis of the earth when the dial is fixed truly , and will cast its shadow on the hour of the day . CONSTRUCTION OF LOGARITHMIC , OR GUNTER'S LINES . To make 24 MATHEMATICAL INSTRUMENTS .
... hypothenuse or axis a g will be parallel to the axis of the earth when the dial is fixed truly , and will cast its shadow on the hour of the day . CONSTRUCTION OF LOGARITHMIC , OR GUNTER'S LINES . To make 24 MATHEMATICAL INSTRUMENTS .
Page 25
John Fry HEATHER. CONSTRUCTION OF LOGARITHMIC , OR GUNTER'S LINES . To make an erect South Dial . - Take the complement of the latitude ... Logarithmic Numbers marked N C - Having fixed upon a convenient length for the entire Gunter's Lines.
John Fry HEATHER. CONSTRUCTION OF LOGARITHMIC , OR GUNTER'S LINES . To make an erect South Dial . - Take the complement of the latitude ... Logarithmic Numbers marked N C - Having fixed upon a convenient length for the entire Gunter's Lines.
Page 26
... logarithm is 2. whereas the logarithmic tables of sines , tangents , & c . , are set down to a radius , of which the logarithm is 10. By taking 8 , then , from each of the tabulated values of the loga- rithmic sines , tangents , & c ...
... logarithm is 2. whereas the logarithmic tables of sines , tangents , & c . , are set down to a radius , of which the logarithm is 10. By taking 8 , then , from each of the tabulated values of the loga- rithmic sines , tangents , & c ...
Page 27
... logarithmic sine of 34 ′ 23 ′′ , being 8.0000669 , will coincide , or nearly so , with the zero point upon our scale , and consequently angles smaller than this cannot be taken off from the sines . This remark applies equally to the ...
... logarithmic sine of 34 ′ 23 ′′ , being 8.0000669 , will coincide , or nearly so , with the zero point upon our scale , and consequently angles smaller than this cannot be taken off from the sines . This remark applies equally to the ...
Page 28
... logarithmic sine rhumbs , marked S.R. , and tangent rhumbs , marked T.R. , are formed in the same way as the lines of logarithmic sines and tangents , but are set off for the angles corresponding to the points and quarter points . of ...
... logarithmic sine rhumbs , marked S.R. , and tangent rhumbs , marked T.R. , are formed in the same way as the lines of logarithmic sines and tangents , but are set off for the angles corresponding to the points and quarter points . of ...
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Common terms and phrases
accuracy adjustment ÆSCHYLUS altitude AMEN CORNER arc of excess arrows astronomical attached azimuth beam compasses bisected brass bubble called chain chords clamp coincide columns compasses construction correct cross wires described diaphragm difference Ditto ditto divided division drawing edge equal extent will reach eye-piece feet figure fixed focal length goniometer graduated Gunter's chain half horizon glass inches index glass instru instrument intersection latitude lens lenses light limb line of collimation line of sines logarithmic marked means measured ment meridian method microscope moved object object-glass observed parallax parallel plate screws pencil perpendicular plane position prism protractor radius rays reading reflected image reflector refracting telescopes refraction represent right angles right ascension round scale sextant side sixth column spirit level square staff station strument survey tangent telescope theodolite transit transverse distance Troughton's tube turning vernier plate vernier scale vertical axis vertical circle zero