Silvanus Phillips Thompson, FRS (1851–1916) began his career in the 1870s when there were still few academic posts for scientists, and when it was still uncertain whether the newer professional ideals would overtake the older, more gentlemanly, ones – in terms of both career advancement and of what being a ‘good’ scientist entailed. Thompson's many scientific, technical and literary activities are discussed in this paper, as is his Quakerism, perhaps the chief motivating force in his life. The paper raises the question of how success in science is measured, and shows how Thompson's sabbatarian impulse influenced both his scientific practice and his pedagogical approach. In detailing the ways in which Thompson made a successful career, despite his lack of professional research focus, the paper relates to larger contexts of science, class, religion and education in late nineteenth-century Britain.