A small, informal, club of pioneering natural philosophers, doctors, and manufacturers, whose members have been called the fathers of the industrial revolution. The name of the society derives from the time of meetings being held at the time of the full moon, allowing travel home after dark. The principal members were the doctor, poet, and inventor Erasmus Darwin, the manufacturer Matthew Boulton, the improver of steam engines James Watt, the potter Josiah Wedgwood, and the chemist and leader of radical dissenters Joseph Priestley. Other important figures were the doctor William Small, the Derby clockmaker, hydraulics expert, and geologist John Whitehurst, and the doctor William Withering, who brought digitalis into mainstream medicine. A more radical note was introduced by two idealistic followers of Rousseau, the voluble, charming, Irish inventor Richard Lovell Edgeworth and the eccentric and wealthy Thomas Day, the author of Sandford and Merton. The members of the Lunar Society passionately believed that their discoveries would make the world a better place. They were the optimistic, and idealistic, forebears of a new class, the nonconformist industrialists and reformers who would dominate nineteenth-century Britain and America.