Definitions of scientific terms; numerous entries on proper names/persons/ incidents. This book attempts to combine conveniently the essential features of dictionary and encyclopaedia. Several Tables are inclded on the dates of Popes, atomic weights, vocabulary, abbreviations, etymology, cross-references, pronunciation, Roman Emperors, Emperors of the Western Empire, Rulers of the United Kingdom, Prime Ministers of Great Britain, Presidents of the USA, States of the USA with their Capitals, Counties and County Towns of the United Kingdom, Chemical Elements,Weights and Measures.