This volume of the eleventh edition of the Encyclopaedia Britannica covers a vast and diverse array of subjects ranging alphabetically from equation to ethics. The first major section is dedicated to mathematical equations, tracing their history from the ancient Rhind papyrus through the contributions of Greek and Arabic mathematicians to Descartes' analytical geometry, alongside detailed methods for solving simultaneous, indeterminate, cubic, and biquadratic equations. The text then delves into the comprehensive real and imaginary theories of algebraic equations, explaining the foundational work of Abel, Galois, and Gauss, including the solubility of equations by radicals and the division of circle and elliptic functions. Following the mathematical treatises, the volume transitions into astronomical and geographical entries, offering precise descriptions of the equation of the centre, the equation of time, and the terrestrial, celestial, and magnetic equators.
Further subjects include the history and offices of the equerry, the classification of the Equidae family of perissodactyle mammals tracing the evolution of the horse from Eocene ancestors, and the physiological and psychological mechanisms of equilibrium and the sense of balance. The historical and constitutional development of the Roman equites is meticulously examined, detailing their transition from a military cavalry division to a distinct financial and political capitalist order under the empire. The volume also explores the complex concept of equity in jurisprudence, contrasting the development of equitable systems under Roman praetors and the English lord high chancellor with the common law. Interspersed throughout are biographical and geographical articles on notable historical figures such as Desiderius Erasmus, Thomas Erastus, and Eratosthenes, alongside entries on the city of Erfurt, ergot, erbium, and the ancient Mesopotamian cities of Erech and Eridu. The text concludes with comprehensive treatments of ethics, culminating in an intellectually rigorous reference work that captures the state of historical, scientific, and literary scholarship at the dawn of the twentieth century.
