Learned societies, such as the Royal Society of London and the Dublin Philosophical Society were a central feature of the scientific revolution of the seventeenth century. This volume shows that a study of the work and membership of these groups is essential before any realistic assessment can be made of the scientific world at this time. Based on a wide range of manuscript and other sources, this book illuminates, by means of an examination of a particular group of natural philosophers, on problems of general interest to all those concerned with the wider aspects of science in this period.