This journal provides immediate access to some articles. Volume 7(9); September 1921 Chemistry The Effect of Temperature and of the Concentration of Hydrogen Ions upon the Rate of Destruction of Antiscorbutic Vitamin (Vitamin C) PMCID: PMC1084895 Mathematics The Average of an Analytic Functional PMCID: PMC1084890 Semi-covariants of a General System of Linear Homogeneous Differential Equations PMCID: PMC1084893 An Algorism for Differential Invariant Theory PMCID: PMC1084894 Physics On the Calculation of the X-Ray Absorption Frequencies of the Chemical Elements PMCID: PMC1084891 On the Calculation of the X-Ray Absorption Frequencies of the Chemical Elements (Second Note) PMCID: PMC1084892 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||