Part 17

Equatorial telescope, explained, 170

Eros, discovered by Witt, 66, 105 its importance, 67

Error of clock, determined by transit, 118

Exposure, length of, in photography, 84

Feldhausen, Herschel's observatory near Capetown, 204

Fiji Islands, their date, 126

Fixed polar telescope, 197

"Following" the stars, 88, 173

Four-day cycle of pole-star, 24

France, outside time-zone system, 129

Fundamental longitude meridian, 124

GALILEO, 47 and the Church, 48 discoveries of, 49 observes Saturn, 141

Galle, discovers Neptune, 61

Gauss, computes first asteroid orbit, 60

Gautier, Paris, constructs big telescope, 179

Geodetic Association, international, 139

Geography, maps, astronomical side of, 112

Geology, polar motion in, 131

Gill, photographs comet, 100

Gilliss, at Naval Observatory, Washington, 169

Goldsborough, at Naval Observatory, Washington, 169

Grande Lunette, Paris, 1900, 176, 180

Gravitation, 13 in Pleiades, 14, 212 law of, Newton's, 212

Gravity, centre of, 217

Greenwich, origin of longitudes, 7, 124 time, 7

Groombridge, English astronomer, 1

Harrison, inventor of chronometer, 8

Head, of heliometer, 156