This journal provides immediate access to some articles. Volume 11(4); April 1925 Chemistry Researches on Selenium Organic Compounds: V. A Simple Method for the Synthesis of 2-Substituted Benzoselenazoles PMCID: PMC1085924 The Density and Atomic Weight of Helium PMCID: PMC1085929 Engineering Determination of the Stresses in a Beam by Means of the Principle of Least Work PMCID: PMC1085923 Mathematics On the Projective and Equi-Projective Geometries of Paths PMCID: PMC1085920 Projective Normal Coördinates for the Geometry of Paths PMCID: PMC1085921 Note on the Projective Geometry of Paths PMCID: PMC1085922 Physics The Reflection of X-Rays by Alkali Halide Crystals PMCID: PMC1085925 Note on the Diffraction of X-Rays by a Wedge-Shaped Slit PMCID: PMC1085926 The Compton Effect with Hard X-Rays PMCID: PMC1085927 The Heat Capacity of Solid Aliphatic Crystals PMCID: PMC1085928 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||