This journal provides immediate access to some articles. Volume 13(10); October 1927 Chemistry The Heterogeneous Thermal Decomposition of Ammonia in Strong Electric Fields PMCID: PMC1085201 The Photochemical Decomposition of Hydrogen-Iodide; the Mode of Optical Dissociation PMCID: PMC1085202 The Detection of Uranium by a Photoluminescence Test PMCID: PMC1085203 Genetics A Working Hypothesis for Segmental Interchange between Homologous Chromosomes PMCID: PMC1085200 Mathematics Groups Generated by Two Operators of Order Three, the Cube of Whose Product is Invariant PMCID: PMC1085198 Some Separation Theorems PMCID: PMC1085199 Physics Absorption of Ultra-Sonic Waves by Hydrogen and Carbon Dioxide PMCID: PMC1085195 On the Fine Structure of Some Mercury Lines PMCID: PMC1085196 On the Duration of the Existence of Doubly Charged Positive Ions in Gases, and Their Detection PMCID: PMC1085197 Statistics Cancer Studies in Massachusetts: 1. The Relationship between Cancer and Density of Population in Massachusetts PMCID: PMC1085204 Zoölogy The Application of Experimental Methods to the Study of Developing Fundulus Embryos PMCID: PMC1085193 The Action of Na, K and Ca Chlorides on the Egg of Fundulus PMCID: PMC1085194 Journal Matter Original table of contents page Administrative content — journal masthead, notices, indexes, etc. | ||