Part 1 Conservation; Chapter 1 The Conservation of Matter and Deformations of a Ball of Modelling Clay; Chapter 2 The Conservation of Weight upon Deformations of a Clay Ball1In collaboration with Kiazim Osman.; Chapter 3 The Conservation of Volume at Equal Concentrations of Matter; Part 2 From Conservation to Atomism; Chapter 4 The Destruction of Matter and the Dissolution of Sugar; Chapter 5 The Conservation of the Sugar and the Beginning of Atomism; Chapter 6 The Conservation of the Weight and Volume of the Dissolved Sugar and the Completion of Atomism; Part 3 Compression, Decompression and Density; Chapter 7 The Expansion of a Maize Seed and of a Column of Mercury1In collaboration with Nelly Gruner.; Chapter 8 Differences in Density; Chapter 9 Special Problems Posed by the Relationship between Weight and Quantity of Matter1In collaboration with Trude Strauss.; Part 4 Formal Compositions; Chapter 10 The Composition of Asymmetrical Relations and Differences in Weight; Chapter 11 Simple and Additive Compositions of Equivalent Weights1In collaboration with Mme Ingold-Favroz-Coune.; Chapter 12 Simple and Additive Compositions of Equivalent Volumes and the Discovery of the Displacement Law;