An introduction to astronomy: designed as a text-book for the use of students in college. By Denison Olmsted ...

ANALYSIS.
PRELIMINARY OBSERVATIONS. Article.
Article. Colures-equinoctial, solstitial....... 36
Astronomy, and its divisions........ 1 Co-ordinates to the equinoctial-right
Descriptive, physical, practical...... 1 ascension, declination............ 87
History.-Ancient nations who culti- Co-ordinlates to the ecliptic, celestial
vated astronomy....... 2 longitude and latitule.................. 87
Pythagoras-his time-his views.... 2 Parallels of latitude............ 38
Alexandrian school-Hipparchus.... 2 Tropics............................ 39
Ptolemy-the Almagest............. 2 Polar circles.................... 40
Copernicus, Tycho Brahe, Kepler, Ga- Zones............................... 41
lileo, Newton, La Place......... 2 Zodiac.. 42
Astrology-Natural-Judicial........ 8 Elevation of the pole............... 43
Accuracy aimed at in astronomy..... 4 Elevation of the equator............ 44
Truths not always to be proved when Polar distance................... 45
stated.......................... 5 Chapter II.-DIURNAL REVOLUTION-ARTICopernican system-its doctrines. 6 FA CBs-TRN c Po Es.
Cnper P coin systk.. t FICIAL GLOBES-ASTRONOMIOAL PROBLEMS.
Plan of the work..........7...... 7
Circles of Diurnal Revolution....... 46
Sidereal day defined..... 47
Appearance of the circles of diurnal
PART I. THE EARTH. revolution. at the equator....... 49
Chapter I.-OF THE FIGURE AND SIZE OF A Parightlel Sphere dene............ 49
THE EARTH, AND THE DOCTRINE OF THE An Oblique Sphere.......... 5
SPHERE. Circle of Perpetual Apparition...... 54
Figure of the earth-proofs......... 8 Circle of Perpetual Occultation...... 55
Dip of the horizon.................. 9 How are the circles of daily motion
Its relation to height-table......... 10 cut by the horizon in the different
The exact form..................... 11 spheres......................... 56
Dimensions of the earth............ 12 Explanation of the peculiar appearHow foun d..................... 13, 14 ances of each sphere, fromi the revoErroneous ideas of up and down..... 15 lutioni of the earth on its axis....57-60
Doctrine of the sphere.............. 16 Artificial Globes-terrestrial and ceSections by a plane................. 17 lestial....................... 61
Axis of a circle-poles............ 18, 19 Meridian - how represented — how
Great circles bisect each other.......... 20 graduated........................ 62
Secondaries....... 21 Horizon-how represented-how graMeasure of inclination.............. 22 duated........................... 62
Terrestrial and celestial spheres..... 23 Hour Circles-how represented...... 63
Horizon-rationall and sensible....... 24 Hour Index described. 64
Zenith and Nadir................... 25 Quadrant of Altitude-its use....... 65
Vertical circles-meridian, prime ver- To rectify the globe for any place.... 66
tical..................... 26 PROBLEMS ON THE TERtRESTRIAL GLOBE
Co-ordinates for the horizon, ampli- -To find the latitude and lowgitude
tude, or azimuth-altitude, or ze- of a place........ 67
nith distance..................... 27 To find a place, its latitude and longiAxis and poles of the earth......... 28 tude being given.................. 68
Equator-equinoctial............. 29 To find the bearing and distance of
Its secondaries-the meridians, or two places... 69
hour circles... 30 To determine the diference of time of
Latitude-polar distance............ 31 two places....................... 70
Longitude..... 32 The hour being given at any place, to
The ecliptic-inclination to the equa- tell what hour it is in any other part
tor....... 33 of the world..................... 71
Vernal and autumnal equinoxes..... 34 To find the antaci l,perieci, and antipoSolstices-signs of the zodiac........ 85 de8............................. 72