This journal provides immediate access to some articles. Volume 7(12); December 1921 Mathematics Group of Isomorphisms of a Transitive Substitution Group PMCID: PMC1084915 Einstein Static Fields Admitting a Group G2 of Continuous Transformations into Themselves PMCID: PMC1084916 Geometric Aspects of the Abelian Modular Functions of Genus Four (II) PMCID: PMC1084917 Physics The Growth and Decay of Photo-thermionic Currents from Oxide Coated Filaments PMCID: PMC1084914 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||