From Artefacts to Atoms

Introduction ; Chapter 1: The origins of the Metre Convention 1851 to 1869 ; Why? ; The need for international agreement on measurement standards ; The great Exhibition of 1851 in London ; The 1855 Paris Universal Exhibition and Statistical Congress ; The Universal Exhibition Paris 1867; a time of political tension in Europe ; The unit of length for geodesy and the original definition of the metre ; The International Conferences on Geodesy, Berlin 1864 and 1867 ; Reactions from France: the Bureau des Longitudes ; Academy of Science of Saint Petersburg ; Reaction from the Academie des Sciences ; Chapter 2: The creation of the International Metre Commission 1869 ; Creation of the Metre Commission ; The members of the French Section of the Metre Commission ; The first meetings of the French Section ; What should be the origin of the new international metre? ; The first meeting of the Metre Commission, August 1870 ; Chapter 3: The International Metre Commission, meetings of 1872/73 ; The order of things from 1869 to 1875 ; The Committee for Preparatory Research April 1872 ; The International Metre Commission September October 1872 ; Chapter 4: The casting of 1874 and the first steps in the fabrication of the new metric standards ; Great Britain decides not to join ; The problem of melting and casting platinum ; Preparations for the Conservatoire casting ; The casting of 250 kilograms of platinum-iridium on 13 May 1874: the alloy of the Conservatoire ; Approval of the Permanent Committee ; First indications that the alloy of the Conservatoire was contaminated with iron and ruthenium ; To proceed regardless ; Chapter 5: The Diplomatic Conference of the Metre 1875 ; The first sessions of the Conference ; The Special Commission ; First drafts of the Convention ; Attempts at a compromise proposal ; The opinion of the French Government ; The first vote on the proposals ; The 12 and 15 April sessions of the Diplomatic Conference ; The signing of the Metre Convention on 20 May 1875 ; Chapter 6: The creation of the BIPM and the beginning of the construction of the new metric prototypes; problems with the French Section ; The first meeting of the International Committee for Weights and Measures ; The founding members of the International Committee ; Choosing the site for the International Bureau, the Pavillon de Breteuil ; Decisions on the main instruments for the new institute ; Progress between April 1875 and April 1876; design for laboratory building ; Difficult relations between the International Committee and the French Section ; First meeting of the International Committee at the Pavillon de Breteuil; the Committee refuses the 1874 alloy ; A new railway line and improved relations with the French Section ; Chapter 7: 1879 to 1889, the first decade of scientific work at the International Bureau ; Progress with metres and instruments ; Publications, official and scientific and the library ; Elections to the International Committee ; Construction of the new prototypes, the metres ; Construction of the new prototypes, the kilograms ; More on the metres ; Good relations with the French Section ; The measurement of temperature, the 1887 hydrogen scale ; A first unsuccessful step towards electrical standards at the BIPM ; Chapter 8: New Member States and the first General Conference on Weights and Measures, 1889 ; New States join including Great Britain ; Time to call a General Conference? ; Final acts of the French Section ; The first General Conference on Weights and Measures September 1889 ; The formal adoption of the new metric prototypes ; The distribution of national prototypes ; In the end, who was right about the alloy of the Conservatoire? ; Chapter 9: The development of the scientific work at the BIPM, the General Conferences of 1895 and 1901 ; More new scientific work ; Thermometry ; The density of water ; The length of the metre in terms of the wavelength of light ; Calibrations ; Staff health problems and building repairs ; Members of the International Committee ; The toise and the Imperial Standard Yard ; The second General Conference and the BIPM pension scheme and reserve fund ; The third General Conference: the BIPM too small and fragile? ; Chapter 10: The creation of the Grands Laboratoires ; Physikalisch-Technische Reichsanstalt (PTR) ; National Physical Laboratory (NPL) ; The National Bureau of Standards (NBS) ; A French national standards laboratory? ; Chapter 11: The story of invar and the extension of the role of the International Bureau at the 6th General Conference 1921 ; The origins of the discovery of invar ; Thermal and mechanical properties of invar ; Samuel Stratton and Sir David Gill and proposals for changing the Convention ; Scientific staff of the Bureau ; The fifth General Conference and proposals for a new temperature scale ; Legal and practical metrology ; The International Bureau 1914 to 1918 ; The meeting of the International Committee in 1920 and the resignation of Foerster ; Plans to broaden the range of the Bureau's work ; The opening of the sixth General Conference 27 September 1921 ; Objections to the new role for the International Bureau ; Final conclusions of the Conference: a new Convention and broader role for the International Bureau ; Chapter 12: The 7th and 8th General Conferences 1927 and 1933, practical metrology and the Bureau during the Second World War ; The financial situation of the Bureau in the 1920s ; Results of the first verification of national prototypes of the metre presented to 7th General Conference ; What should be the standard temperature for the definition of the metre and for industrial length metrology? ; Quartz reference standards for length and proposals for a new definition of the metre ; Agreement for work on electrical standards at the International Bureau and the creation of the Consultative Committee for Electricity ; The International Temperature Scale of 1927 ; The beginning of electrical work at the International Bureau ; The move to absolute electrical units ; A Consultative Committee for Photometry and the CIE, new definition of the standard of light ; The International Committee takes an important decision related to practical metrology ; Other activities of The International Committee and international Bureau in the 1930s ; The International Bureau during the Second World War ; Scientific work during the War ; Chapter 13: The SI, absolute electrical units, the International Committee and the creation of the ionizing radiation section. ; The call for an International System of Units at the 9th General Conference 1948 ; The substitution of absolute electrical units for the 1908 International Units ; Objections on the part of the PTR ; A date for implementation of the absolute system and interruption caused by the war ; The need to act quickly ; Final decisions of the International Committee ; Final discussions on practical metrology ; New science, new prospects for units ; The International Committee after the war ; The International Bureau and its staff after the war, the Accord de Siege ; The creation of the Ionizing Radiation Section at the Bureau ; Chapter 14: The adoption of the SI, revising the Metre Convention, new definitions of the metre and second at the 11th General Conference 1960 ; The International System of Units SI ; Preparations to revise the Metre Convention ; Discussions at the 11th General Conference ; The change in definition of the Metre: arguments for and against ; Which radiation to choose? ; The new definition of the metre and the International Bureau ; Financial matters and problems of the Cold War ; The definition of the second ; The International Committee decides ; Problems with the new definition of the second ; The second redefined again in 1967 ; The development of the scientific work of the International Bureau up to 1975 ; The influence on the Bureau of national standards laboratories ; The influence of the Consultative Committees ; Laser wavelength standards at the Bureau ; Staff development at the Bureau ; Calibrations: an evolving activity at the Bureau ; The new journal, Metrologia ; Chapter 15: The mole, the speed of light and more about the Metre Convention ; The mole and chemistry ; The first attempt to bring chemistry into the affairs of the Bureau ; The 13th CGPM and its refusal to adopt the dotation ; The Centenary of the Metre Convention in 1975 ; Redefinition of the metre in terms of the speed of light ; New proposals to modify the Metre Convention ; The Direction and supervision of the International Bureau from 1975 to 2003 ; The financial situation of the BIPM from 1975 to 2003 ; The Pavillon du Mail, some difficulties with building permission ; Chapter 16: New science at the BIPM and the Recognition of National measurement Standards ; The BIPM staff in the last quarter of the 20th century ; Developments in photometry and radiometry and a new definition of the candela ; International Atomic Time and Coordinated Universal Time ; Other new science at the Bureau ; The new quantum electrical standards ; The BIPM mechanical workshop ; Chemistry at last comes to the CIPM and BIPM ; Traceability in laboratory medicine ; The International Organization for Legal Metrology ; The CIPM Mutual Recognition Arrangement for National Measurement Standards - early discussions ; First moves towards an MRA ; Regional metrology organizations ; Other pressures on national laboratories and looking to the BIPM ; First meeting of Directors of national metrology institutes and first draft of an MRA ; Quality systems and key comparison reference values ; Final agreement reached ; Chapter 17: The redefinition of the kilogram and the move towards the New SI ; The kilogram from 1889 to the present day ; Advances in science that at last make absolute units possible ; The watt balance ; Determine the mass of an atom by x-ray crystal density of silicon ; Comparing the results from the watt balance and the silicon crystal density experiments ; How and when to proceed to an actual redefinition of the kilogram ; What does it mean to fix the numerical value of a fundamental constant and how do we use it to define a unit? ; The arguments against a new definition ; Redefining the ampere, kelvin and mole ; How to formulate the new definitions ; The CIPM proposes an absolute system of units based on the fundamental constants of physics ; Epilogue: The new SI and the future role of the BIPM ; Appendix English text of the Metre Convention ; Bibliography