François Arago (eBook)

James Lequeux completed his PhD thesis in radioastronomy in 1962 and was an assistant, then associate, professor of physics and astronomy at Paris University until 1966. He was an Astronomer from 1966-1999 and an invited scientist at CalTech from 1968-1969. Dr. Lequeux was also the Director of the Marseilles Observatory from 1983-1988 and was Editor-in-Chief of the journal Astronomy & Astrophysics for 15 years. He retired in 1999 and then began work on the history of astronomy, a subject he presently writes about. Dr. Lequeux has published over 403 papers and five books, including The Interstellar Medium (Springer 2005) and Le Verrier: Magnificent and Detestable Astronomer (Springer 2013).

Preface 6
Acknowledgements 10
Contents 12
Chapter 1: Scientific Life in France at the Time of Arago 17
The Great Scientific Institutions 18
The Academy of Sciences 18
Some Other Scientific Societies 22
The Board of Longitudes 23
The Grandes Écoles 25
The École Polytechnique 26
The École Normale Supérieure 28
The Conditions for Scientific Research 29
The Nature of Research 29
Science and Society 31
Financing Research 32
Publications 33
An International Science 37
Chapter 2: The Life of Arago 38
The Arago Family 39
Youth (1756–1809) 42
The Catalan Odyssey 44
The Friendship of Humboldt 45
The Time of Major Scientific Activity (1809–1830) 47
Elected to the Academy of Sciences 47
Professor at the École Polytechnique 49
The Scientific Work 50
At the Observatory 53
The Politician (1830–1838) 55
The Deputy 56
The 1848 Revolution22 60
The Abolition of Slavery 62
The End of a Dream 63
The Last Years 66
Chapter 3: The Nature of Light 71
The Precursors 71
The Polarization of Light 77
What Is Polarization? 77
Malus and the Discovery of Polarization 82
Arago’s Contribution 83
Arago and Fresnel 87
Fresnel’s Come Out 87
Fresnel and Arago in Paris 91
Infrared and Ultraviolet 98
Chapter 4: The Velocity of Light 102
The Constancy of the Velocity of Light 103
The Aberration of Light 103
John Michell and the Variations of the Velocity of Light 104
Arago’s Experiment 106
The Intervention of Fresnel 110
Fizeau’s Experiment 112
The Modern Interpretation of Arago’s and Fizeau’s Experiments 115
Arago’s “Crucial Experiment” 117
The Rotating Mirror 117
Fizeau and Foucault Pick Up the Torch 119
Problems of Deontology 120
The Direct Measurement of the Velocity of Light 122
The Precursors 122
Fizeau’s Toothed Wheel 125
The Velocity of Light After Fizeau and Arago 127
Chapter 5: The Birth of Electromagnetism 132
The Electric Battery 132
Œrsted’s Experiment 135
Ampère’s First Experiments 138
Arago Intervenes 140
Arago and Faraday: Transformation of Energy 142
The First Electric Motors 142
The “Magnetism of Rotation” 145
Controversies 146
The Discovery of Induction 147
Arago’s Stubbornness 148
Faraday and the Magnetic Field 149
Wild Imaginings and Discoveries on Electricity 150
Some of the First Applications of Electricity 151
The Electric Telegraph 151
Electric Motors 155
Magnetos and Dynamos 156
Chapter 6: Measuring the Earth 161
Geodesy Before Arago 161
The Origins 161
The Length of the Degree and the Shape of the Earth 164
The Beginnings of Gravimetry 165
Geodesy and Cartography: The Cassini Map of France 166
Triangulations at the End of the Eighteenth Century 168
Measuring the Paris Meridian During the French Revolution 172
Arago’s Work 176
Extending the Measurements of the Meridian to the Balearic Islands: Should One Change the Length of the Meter? 176
The New Geodesic Linkage of France and England 179
Leveling and New Maps of France 182
Leveling 182
New Maps of France 182
Chapter 7: Arago and the Paris Observatory 184
The Paris Observatory Before Arago 185
The Beginnings 185
Eighteenth Century Improvements 189
The Observatory of the Board of Longitudes13 191
The Observatory upon Arago’s Arrival 191
The Instruments of Arago 191
The Great Equatorial Telescope of the East Tower19 195
The Amphitheater 200
Life at the Observatory 200
The Astronomers and the Arago Clan 200
The Visitors 203
The Observations 205
The Le Verrier Affair32 207
The Observatory at Arago’s Death 212
Chapter 8: Arago Astronomer 214
Astronomy in France in Arago’s Time 215
The Triumph of Newtonian Mechanics 215
William Herschel’s Contribution 216
The Program of the Board of Longitudes 218
Astrometry at the Paris Observatory 220
Proper Motion and Parallax 221
Arago’s Micrometer 225
The Polarization of Light and the Physical Nature of Celestial Bodies 227
The Moon 227
The Sun 228
Solar Total Eclipses 230
Stars 231
Comets 233
Photometry 235
The Limb Darkening of the Solar Disk 236
The Brightness of the Sky, and Stellar Photometry 239
Scintillation, Seeing and the Diameter of Stars 242
Arago’s Explanation 242
Arago’s Scintillometer 244
The Diameter of Stars 244
Chapter 9: Arago Geophysicist and Meteorologist 246
Arago and Meteorology 248
The Birth of Scientific Meteorology 248
Meteorological Forecast 248
A Synoptic Approach 250
Storms, Lightning and Waterspouts 250
The Red Moon 252
Atmospheric Optics 254
Terrestrial Magnetism 255
Arago’s Measurements 256
Diurnal Variations of the Earth’s Magnetic Field 257
Magnetic Field and Polar Aurorae 259
The Origin of the Terrestrial Magnetic Field 261
A Synoptic View of the Terrestrial Magnetic Field 261
The Temperature of the Earth 263
Oceanography 265
The Detection of Reefs 266
Currents 266
A Method for Oceanography 268
Chapter 10: Applied Physics 270
The Optical Properties of Gases 271
The First Measurements 271
The Refractive Power: A Stone in Newton’s Backyard 272
Interferential Measurements 273
Arago and the Lighthouses 274
A Short History of Lighthouses 274
Arago and Fresnel Intervene 275
The Fresnel Lenses 277
The Velocity of Sound 279
The “Elastic Force” of Water Vapor 280
Chapter 11: The Promotion of Science and Technique 283
The Popularization of Science 283
The Public Lectures in Astronomy and the Astronomie Populaire 283
Discourses and Interventions at the Chamber of Deputies 287
At the Academy of Sciences 288
The Scientific Notices 289
The Steam Engine and the Industrial Progress 290
Improvements and Dangers of the Steam Engine 290
The Birth of Thermodynamics 293
A Few Curiosities 295
The Economic and Social Consequences of the Steam Engine 298
The Railways 299
The Beginnings 299
The Parisian Railways and the Intervention of Arago 300
Banks or State? 301
Two False Trails: The Atmospheric Railway and the Arnoux System 302
A Pioneer of Photography 306
The Beginnings 307
Arago’s Presentations at the Academy of Sciences 307
The First Astronomical Photographs 309
The Water Supply of Paris and the Artesian Wells 310
Chapter 12: Arago’s Legacy 315
Funeral and Discourses 315
Other Times, New Dispositions 318
Péreire at Estagel 319
The Third Republic 321
Modern Times 323
Magnificence and Decadence of French Physics and Astronomy in the Nineteenth Century 324
Bibliography 327
Writings by Arago 327
Books and Documents on Arago 327
Other Ancient Books 329
Some Selected Other Books 332
Some Useful Internet Sites 333
Index 334