| FIG. | | PAGE |
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| 1. | The heavens according to Ptolemy | 3 |
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| 2. | The zodiac of Denderah | 7 |
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| 3. | Illustration of Euclid’s statements | 10 |
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| 4. | The plane of the ecliptic | 13 |
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| 5. | The plane of the ecliptic, showing the inclination of the earth’s axis | 14 |
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| 6. | The first meridian circle | 20 |
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| 7. | The first instrument graduated into 360° (west side) | 21 |
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| 8. | Astrolabe (armillÆ ÆquatoriÆ of Tycho Brahe) similar to the one contrived by Hipparchus | 26 |
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| 9. | Ecliptic astrolabe (the armillÆ zodiacales of Tycho Brahe), similar to the one used by Hipparchus | 28 |
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| 10. | Diagram illustrating the precession of the equinoxes | 31 |
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| 11. | Revolution of the pole of the equator round the pole of the ecliptic caused by the precession of the equinoxes | 32 |
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| 12. | The vernal equinox among the constellations, B.C. 2170 | 34 |
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| 13. | Showing how the vernal equinox has now passed from Taurus and Aries | 34 |
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| 14. | Instrument for measuring altitudes | 35 |
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| 15. | Portrait of Tycho Brahe (from original painting in the possession of Dr. Crompton, of Manchester) | 39 |
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| 16. | Tycho Brahe’s observatory on the island of Huen | 43 |
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| 17. | Tycho Brahe’s system | 46 |
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| 18. | The quadrans maximus reproduced from Tycho’s plate | 48 |
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| 19. | Tycho’s sextant | 50 |
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| 20. | View and section of a prism | 56 |
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| 21. | Deviation of light in passing at various incidences through prisms of various angles | 57 |
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| 22. | Convergence of light by two prisms base to base | 59 |
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| 23. | Formation of a lens from sections of prisms | 60 |
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| 24. | Front view and section of a double convex lens | 61 |
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| 25. | Double concave, plane concave, and concavo-convex lenses | 61 |
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| 26. | Double convex, plane convex, and concavo-convex lenses | 62 |
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| 27. | Convergence of rays by convex lens to principal focus | 62 |
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| 28. | Conjugate foci of convex lens | 63 |
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| 29. | Conjugate images | 64 |
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| 30. | Diagram explaining Fig. 29 | 64 |
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| 31. | Dispersion of rays by a double concave lens | 65 |
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| 32. | Horizontal section of the eyeball | 66 |
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| 33. | Action of e
| 255 |
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| 123. | System of wires in transit eyepiece | 257 |
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| 124. | The Greenwich chronograph. (General view) | 261 |
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| 125. | Details of the travelling carriage which carries the magnets and prickers. (Side view and view from above) | 262 |
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| 126. | Showing how on the passage of a current round the soft iron the pricker is made to make a mark on the spiral line on the cylinder | 263 |
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| 127. | Side view of the carriage carrying the magnets and the pointer that draws the spiral | 263 |
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| 128. | Wheel of the sidereal clock, and arrangement for making contact at each second | 266 |
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| 129. | Arrangement for correcting mean solar time clock at Greenwich | 268 |
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| 130. | The chronopher | 276 |
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| 131. | Reflex zenith tube | 286 |
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| 132. | Theodolite | 288 |
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| 133. | Portable alt-azimuth | 289 |
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| 134. | The 40-feet at Slough | 294 |
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| 135. | Lord Rosse’s 6-feet | 295 |
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| 136. | Refractor mounted on alt-azimuth tripod for ordinary star-gazing | 296 |
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| 137. | Simple equatorial mounting | 298 |
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| 138. | Cooke’s form for refractors | 300 |
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| 139. | Mr. Grubb’s form applied to a Cassegrain reflector | 301 |
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| 140. | Grubb’s form for Newtonians | 303 |
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| 141. | Browning’s mounting for Newtonians | 304 |
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| 142. | The Washington great equatorial | 309 |
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| 143. | General view of the Melbourne reflector | 312 |
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| 144. | The mounting of the Melbourne telescope | 313 |
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| 145. | Great silver-on-glass reflector at the Paris observatory | 316 |
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| 146. | Clock governor | 319 |
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| 147. | Bond’s spring governor | 320 |
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| 148. | Foucault’s governor | 323 |
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| 149. | Illuminating lamp for equatorial | 325 |
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| 150. | Cooke’s illuminating lamp | 326 |
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| 151. | Dome | 338 |
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| 152. | Drum | 338 |
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| 153. | New Cincinnati observatory—(Font elevation) | 338 |
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| 154. | Cambridge (U.S.) equatorial | 339 |
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| 155. | Section of main building—United States naval observatory | 341 |
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| 156. | Foucault’s siderostat | |
