This journal provides immediate access to some articles. Volume 6(11); November 1920 Agriculture A Critical Study of Fertilizer Experiments PMCID: PMC1084676 Astronomy New Observations on the Variability of the Sun PMCID: PMC1084673 Genetics Homologous Genes and Linear Linkage in Drosophila virilis PMCID: PMC1084666 The Mutant Crossveinless in Drosophila Melanogaster PMCID: PMC1084670 Is Crossing Over a Function of Distance? PMCID: PMC1084671 Interspecific Hybrids in Crepis: I. Crepis capillaris (L) Wallr. × C. tectorum L. PMCID: PMC1084672 Mathematics Semivariants of a General System of Linear Homogeneous Differential Equations PMCID: PMC1084668 The Permanent Gravitational Field in the Einstein Theory PMCID: PMC1084674 Physics The Intensities of X-Rays of the L-Series: III. Critical Potentials of the Platinum and Tungsten Lines PMCID: PMC1084667 Some New Methods in Interior Ballistics PMCID: PMC1084669 Statistics A Simpeified Method for the Statistical Interpretation of Experimental Data PMCID: PMC1084675 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||