Part 16

Circle, meridian, explained, 189

Clerk Maxwell, discusses Saturn's rings, 146

Clock, affected by temperature, 117 affected by barometric pressure, 117 astronomical, 115 astronomical, how mounted, 116 astronomical, its dial, 116 error of, determined with transit, 118 jeweller's regulator, 114 of telescope, 175

Clusters of stars, photography of, 98

Columbia University Observatory, latitude observations, 139 polar photography, 196

Common, his reflecting telescope, 32

Confusion of dates, in Pacific Ocean, 125

Congress of Astronomers, Paris, 1887, 102

Constellations, 162

Control, "mouse," for photography, 88

Copernican theory of universe, 53, 56 demonstration, 94

Corkscrew tunnels, 220

Crape ring of Saturn, 144

Cumulative effect, in photography, 84

Date, confusion of, in Pacific Ocean, 125

Date-line, international, explained, 126

Development of photograph, 81

Dial, of astronomical clock, 116

"Dialogue" of Galileo, 53

Differences of time, explained, 121

Directions, telescopic measurement of, 21

Directory of the heavens, 103

Distance, of light-source in photography, 83 of stars, 94, 106, 158 of Sun, 67, 97, 106

Donner, polar photography, 195

Double telescopes, for photography, 86

Earth, motions of its pole, 131 rotation of, 136, 162, 171, 184 shape of, 135

Eclipses, photography of, 109

Elkin, measures Pleiades, 15