xx
Contents
5.4 Collaborating with David Gill
74
5.5 France and the International Organization of Science
80
5.6 Carte du Ciel
82
5.7 The Kapteyn Household
87
6
Laboratory and Statistical Astronomy
91
6.1 The Astronomical Laboratory
92
6.2 Stars and Galaxies
96
6.3 Parallaxes and Proper Motions
102
6.4 Willem de Sitter
107
6.5 Secular Parallax
110
6.6
Spatial Distribution of Stars
113
6.7 Natural Sciences Society
115
7
Star Streams
121
7.1 Gill, Donner, Newcomb
121
7.2
St. Louis
126
7.3
Star Streams
128
7.4 Further Travels in America
134
7.5 Parallaxes Again
136
7.6 Plan of Selected Areas
141
8
In the Meantime in Groningen
149
8.1
Lectures
149
8.2
Anecdotes
152
8.3
Character
155
8.4 Weersma, Yntema, van Rhijn
163
9
Mount Wilson
171
9.1 Hale and Kapteyn
174
9.2
First Visit, 1908
177
9.3
Kapteyn Cottage
178
9.4
Dust
183
9.5 Interstellar Extinction
188
9.6 The Solar Union Congress, 1910
192
9.7
Results of the Visits to Mount Wilson
195
9.8
End of an Era
200
10 Statistics and Other Concerns
203
10.1 Tides
206
10.2 Statistics
208