Our epigraphs serve two purposes. First, they disrupt the classification, by contemporaries and historians, of Tyndall as an expert and Lewes as a popularizer. John Tyndall (1820–93), although an expert experimental physicist and member of the scientific elite, was by the end of his life better known as a popularizer, or‘expositor’, of science. George Henry Lewes (1817–78), by occupation a journalist, critic and popular writer, tried to establish his credentials as a scientific researcher. Here, Lewes is praised for his expertise and Tyndall praised, backhandedly, for ‘distinction in the popular field’.

Second, the epigraphs hint at the contested nature of scientific authority in Victorian Britain. Tait's criticism of Tyndall was made during a series of bitter exchanges. His hostility was driven by personal antagonism, philosophical objections to Tyndall's metaphysical naturalism and nationalist indignation at Tyndall's denigration of Tait's fellow Scottish natural philosophers.