Precise dimensions : a history of units from 1791-2018 / Malcolm Cooper, Jim Grozier.

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Preface -- Introduction -- Glimpses in brief -- 1. The metre and the metric system -- part 1. The making of the metre -- 1.1. Introduction -- 1.2. The birth of the metric system -- 1.3. The Meridian Expedition -- 1.4. How the Meridian was measured -- 1.5. From angles to metres -- 1.6. Measuring the base lines -- 1.7. Crunching the numbers -- 1.8. Extrapolation to the quadrant -- 1.9. Conclusion

part 2. The metre convention and the BIPM -- 1.10. The archive metre shows its age -- 1.11. The international consensus : 1864-1875 -- 1.12. The metre convention : 1 March to 20 May 1875 -- 1.13. The metric system in the 20th and 21st centuries

2. From notion to precision : the SI second -- 2.1. Ancient times -- 2.2. The mechanical clock -- 2.3. The pendulum -- 2.4. Pursuing precision -- 2.5. Earth abandoned? -- 2.6. Electronics appear -- 2.7. Independent standards -- 2.8. Conclusions

3. Lord Rayleigh's determination of the ohm -- 3.1. Introduction -- 3.2. The rotating coil method -- 3.3. Value of the BA unit of resistance as determined by Rayleigh -- 3.4. The Lorenz method -- 3.5. The mercury standard -- 3.6. Subsequent developments and modern resistance standards

4. Temperature scales : past, present and future : 1700-2050 -- 4.1. Introduction -- 4.2. de facto temperature scales : 1700-1900 -- 4.3. Towards defined temperature scales -- 4.4. The demise of defined temperature scales? -- 4.5. Summary

5. Kelvin's absolute temperature and its measurement -- 5.1. Thomson's motivations for absolute temperature -- 5.2. The absolute as the abstract -- 5.3. The operationalization of Thomson's first absolute temperature -- 5.4. Thomson's second concept of absolute temperature -- 5.5. The operationalization of the second concept -- 5.6. Iterative operationalization

6. A brief history of the unit of chemical amount -- 6.1. Comparative measurements -- 6.2. Quantitative measurements -- 6.3. The mass unit of the chemist : the gram-molecule -- 6.4. The many atomic weight scales -- 6.5. The name : mole -- 6.6. Molar measurements in practice -- 6.7. Amount of substance as a dimensional quantity -- 6.8. The Avogadro number -- 6.9. Proposed new definition of the mole -- 6.10. Consequences of the entity-based definition -- 6.11. Outlook

7. The history of the SI unit of light, the candela -- 7.1. Introduction : light and vision -- 7.2. Artefact-based standards and units for measurement of 'light' -- 7.3. A radiometric approach to photometry -- 7.4. A look to the future

8. The story of mass standards 1791-2018 -- 8.1. Introduction -- 8.2. Construction of the kilogram of the archives -- 8.3. William Hallowes Miller and the New Imperial Standard Pound -- 8.4. The metre convention, the BIPM and the international prototype of the kilogram -- 8.5. Relative stability of national and international prototypes -- 8.6. The new definition of the kilogram -- 8.7. Realisation of the kilogram using the silicon x-ray crystal density method : Si[rightwards arrow]SI -- 8.8. Conclusion -- 9. Mass from energy--a unit for a quantum world.

Units are the foundation for all measurement of the natural world, and from which standard, our understanding develops. This book, stemming from a conference on the history of units organised by the editors, provides a detailed and discursive examination of the history of units within physics, in advance of the proposed redefinition of the SI base units at the General Conference on Weights and Measures in 2018. It features contributions from leading researchers in metrology and history.