This journal provides immediate access to some articles. Volume 6(4); April 1920 Botany The Formation of the Cell Plate in the Cambium of the Higher Plants PMCID: PMC1084462 Chemistry The Influence of Ions on the Osmotic Pressure of Solutions PMCID: PMC1084465 Genetics The Evidence for the Linear Order of the Genes PMCID: PMC1084455 The Arrangement of Genes in Drosophila Virilis PMCID: PMC1084456 A Contribution of Genetics to the Practical Breeding of Dairy Cattle PMCID: PMC1084468 Geology Differentiation by Deformation PMCID: PMC1084454 Mathematics The Starting of a Ship PMCID: PMC1084460 A Thermodynamic Study of Electrolytic Solutions PMCID: PMC1084461 Functionals Invariant under One-Parameter Continuous Groups of Transformations in the Space of Continuous Functions PMCID: PMC1084463 Physics The Functions of Intensity and Phase in the Binaural Location of Pure Tones PMCID: PMC1084457 The Measurement of Small Time Intervals and Some Applications, Principally Ballistic PMCID: PMC1084458 Charcoal Activation PMCID: PMC1084459 Physiology Thermokinetics of Liometopum Apiculatum Mayr PMCID: PMC1084464 Psychology A Study of the Persistence of Vision PMCID: PMC1084467 Zoology Evidence on the Nature of Nuclear Activity PMCID: PMC1084466 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||