This symposium was held at the College de France in Paris from August 31 to Sep­ tember 4, 1970. The Organizing Committee consisted of V. Bumba, R. Howard (Chairman), K. O. Kiepenheuer, R. Michard, E. N. Parker, A. B. Severny, V. E. Stepanov, and T. Takakura. The Local Organizing Committee consisted of Miss G. Drouin (Secretary), R. Michard (Chairman), J. -C. Pecker, and J. Rayrole. We are indebted to the College de France for their kind hospitality. I wish to express my gratitude to members of the Organizing Committee for advice and assistance and to R. Michard and the Local Organizing Committee, who were responsible for the smooth running of the sessions, the distribution and collection of the discussion sheets, and for a delightful Wednesday afternoon excursion to Meudon. It is a pleasure to thank J. W. Evans, V. E. Stepanov, K. O. Kiepenheuer, R. G. Giovanelli, T. G. Cowling, V. Bumba, W. C. Livingston, and J. M. Wilcox who kindly served as session chairmen. I also wish to thank Miss Judy Harstine and John M. Adkins of the Hale Observatories, for invaluable assistance in editing the proceedings. This Symposium has been supported financially by the International Astronomical Union.

Inhalt

I / Instrumentation - Measurement of Magnetic Fields in the Solar Atmosphere.- 1. The Measurement of Solar Magnetic Fields.- 2. The Culgoora Magnetograph.- 3. A Complete Stokes Vector Polarimeter.- 4. Measurements of Magnetic Fields.- 5. Digital Videomagnetograms in Real Time.- 6. The Kitt Peak Magnetograph. IV: 40-Channel Probe and the Detection of Weak Photospheric Fields.- 7. A Pressure Scanning Fabry-Pérot Magnetometer.- 8. Sacramento Peak Magnetograph.- 9. Systematic Errors of the Crimean Vector Magnetograph (presented by A. Severny).- 10. Analog Video Magnetograms in Real Time.- 11. A New Completely Digitized Filter Magnetograph.- 12. Difficulties in the Simultaneous Measurement of all Stokes Parameters.- 13. Reduction of the Parasitical Signal of Circular Polarization on an Antenna of Variable Profile with the Help of a Grating.- 14. A Short Report on the Magnetic Beam Absorption Filter Research at the Rome Astronomical Observatory.- II / The Interpretation of Magnetograph Results - The Formation of Absorption Lines in a Magnetic Field.- 15. The Interpretation of Magnetograph Results: The Formation of Absorption Lines in a Magnetic Field.- 16. Coherence Properties of Polarized Radiation in Weak Magnetic Fields.- 17. Paschen-Back Effect of the Lithium Resonance Doublet in Sunspots.- 18. The Crossover and Magneto-Optical Effects in Sunspot Spectra.- 19. The Effect of Collisions on Spectral Line Formation in Solar Magnetic Regions.- 20. Line Formation in Inhomogeneous Magnetic Fields (presented by W. Mattig).- III / Observations of Sunspot and Active Region Magnetic Fields.- 21. On Magnetic Fields in Sunspots and Active Regions.- 22. Magnetic Field and Turbulence in Sunspots.- 23. Photoelectric Measurements of Sunspot Magnetic Fields.- 24. Observations of Magnetic Fields in Quiescent Prominences.- 25. Some Remarks on the Statics and Dynamics of Magnetic Field Structure Development in Active Regions.- 26. I On the Structure of Magnetic Field and Electric Currents of a Unipolar Sunspot (presented by A. Severny).- 27. Magnetic Field Strengths Derived from Various Lines in the Umbral Spectrum.- 28. The Magnetic Fields at Different Levels in the Active Regions of the Solar Atmosphere (presented by N. V. Steshenko).- 29. Observations of the Two-Level Structure of Sunspot Magnetic Fields (presented by N. S. Soboleva).- 30. On the Circular Polarization in Active Regions.- 31. Application of the Chromospheric Magnetograph to Active Regions (presented by P. Foukal).- 32. Evolution of the Magnetic Field Configuration in an Active Region.- 33. Line Profiles in Sunspot Umbrae and Penumbrae by Atomic Beam Spectroscopy.- 34. On the Fine Structure of the Magnetic Field in the Undisturbed Photosphere.- 35. Supergranulation at the Center of the Disk.- 36. Magnetographic and Spectrographic Observations of Weakly Active Regions.- 37. The Magnetic and Velocity Fields and Brightness in the Solar Atmosphere (presented by N. V. Steshenko).- 38. Magnetic Fields Measured with the 10830 Å HeI Line.- 39. Observations and Interpretation of Supergranule Velocity and Magnetic Fields.- 40. Vertical Velocities Associated with Plage Region Magnetic Fields.- 41. Spectra-Spectroheliograph Observations.- 42. The Time Dependence of Magnetic, Velocity, and Intensity Fields in the Solar Atmosphere.- 43. On the Reality of Magnetic Fine Structure.- 44. H? Structures and Small-Scale Magnetic Field Configurations.- 45. Magnetic Field Spectroheliograms from The San Fernando Observatory.- 46. On the Time Fluctuations of Magnetic Fields.- 47. Five-Minute Oscillations in the Solar Magnetic Field.- 48. N. V. Steshenko / The Fine Structure of Magnetic Fields and Velocities in Sunspots. (No text nor summary was communicated by the author.).- 49. Y. D. Zhugzda The Oscillatory Convection in Penumbrae. (No text nor summary was communicated by the author.).- IV / Observations of Magnetic Fields Associated with Flares and other Transitory Phenomena.- 50. Solar Magnetic Fields in Association with Flares.- 51. On Coronal Instability and Moving Radio Features Associated with a Flare Spray.- 52. Magnetic Fields Associated with Solar Flares.- 53. Sunspot Magnetic Fields and High Energy Electrons in Flares.- 54. The X-Ray Corona and the Photospheric Magnetic Field.- 55. Magnetic Fields in the Lower Corona Associated with the Expanding Limb Burst on March 30th 1969 Inferred from the Microwave High-Resolution Observations.- 56. Electric Currents Connected with the Proton Flares of 7 July and 2 September, 1966.- 57. Observations of Magnetic Field Changes in Active Regions.- 58. The Magnetic Fields and the Polarization of Radio Emission in the Active Center of October 1968.- 59. The Position Regularities of Flares Related to the Field Maximum in Sunspot Groups (presented by G. V. Kuklin).- 60. An Attempt to Associate Observed Photospheric Motions with the Magnetic Field Structure and Flare Occurrence in an Active Region.- 61. Volume Characteristics of Magnetic-Channel Flares.- 62. The Relation Between Dashes and Flares (Physical Nature of the Dash Phenomena) (presented by N. S. Soboleva).- V / Theories of Small Scale Magnetic Fields.- 63. Theories of Small-Scale Magnetic Fields.- 64. Sunspot Magnetic Fields and Umbral Dots.- 65. Statistical Model of Small Scale Discrete Structure of Magnetoplasma in Active Regions of the Sun.- 66. Evolution of Turbulent Magnetic Fields - Approach to a Steady State.- 67. Distribution of the Magnetic Force in the Surface Layers of Sunspots.- 68. Observation of Solar Flare Type Processes in the Laboratory.- 69. Interaction of Coronal Material with Magnetic Fields.- 70. The Possibility of Magnetic Field Origin in Fine Structure Elements of Solar Features.- 71. Anisotropy of Electric Conductivity and Dissipation of Magnetic Fields.- VI / Optical and Radio Observations of Large Scale Magnetic Fields on the Sun.- 72. Large Scale Solar Magnetic Fields and Their Consequences.- 73. Coronal Magnetic Fields Above Active Regions.- 74. Experimental Study of the Orientation of Magnetic Fields in the Corona.- 75. Time Evolution of the Large-Scale Solar Magnetic Field.- 76. The Magnetic Field Structure in the Active Solar Corona.- 77. Optical and Radio Observations of Large Scale Magnetic Fields on the Sun.- 78. 80 MHz Radioheliograph Evidence on Moving Type IV Bursts and Coronal Magnetic Fields.- 79. Active Regions at Millimeter Wavelengths and the Measurement of Magnetic Fields.- 80. Radio-Astronomical Evidence for Magneto-Hydrodynamical Pulsations in the Corona.- 81. On the Orientation of Magnetic Fields in Quiescent Prominences.- 82. Observations of the Coronal Network.- 83. Preliminary Results of Spectroscopic Determination of the Coronal Rotation.- VII / The Polar Fields of the Sun a…