From Artefacts to Atoms: The BIPM and the Search for Ultimate Measurement Standards

by Terry Quinn

Overview

The International Bureau of Weights and Measures (BIPM) is currently implementing the greatest change ever in the world's system of weights and measures — it is redefining the kilogram, the final artefact standard, and reorganizing the system of international units. This book tells the inside story of what led to these changes, from the events surrounding the founding of the BIPM in 1875 — a landmark in the history of international cooperation — to the present. It traces not only the evolution of the science, but also the story of the key individuals and events.

The BIPM was the first international scientific laboratory. Founded in 1875 by the Metre Convention, its original tasks were to conserve the new international standards of the metre and the kilogram, to carry out calibrations for Member States and undertake research to advance measurement science. The book is based on the substantial archive of the BIPM which, from the very beginning, recounts the many discussions and arguments first as to whether and how such an institute should be created and in due course, how over the next one hundred and thirty years it should develop. Despite many national and personal rivalries, the institute actually created was admirably suited to its declared tasks. In the years and decades that followed, the scientific work of the small group of men who made up its first staff was of a very high order. One of the early Directors received the Nobel Prize for physics in 1920 for his discovery of invar. The international governing Board of the institute, the International Committee of Weights and Measures, has guided the institute from one charged with the conservation of the prototype artefacts to one now at the centre of world metrology and preparing for the redefinition of the last remaining artifact, the kilogram, in terms of a fixed value for one of the fundamental constants of physics, the Planck constant

Product Details

ISBN-13:	9780195307863
Publisher:	Oxford University Press
Publication date:	11/04/2011
Pages:	440
Product dimensions:	7.30(w) x 10.00(h) x 1.30(d)

About the Author

Terry Quinn is an experimental physicist who has worked in a number of fields of measurements science: temperature, optical radiometry, mass and fundamental constants. From 1988 to 2003 he was Director of the International Bureau of Weights and Measures, Sevres, France and was much involved in the organization of international metrology. He is a Fellow of the Royal Society of London.

Table of Contents

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 Académie 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 Siège
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