At the conclusion of Henry James's 1896 novel The Spoils of Poynton, the protagonist Fleda Vetch struggles to articulate her sense of the ‘vivid presence of the artist's idea’ she perceives in the maiden-aunt's house at Ricks: ‘It's a kind of fourth dimension. It's a presence, a perfume, a touch. It's a soul, a story, a life. There's ever so much more here than you and I!’ Her ability to perceive this presence makes her ‘the one who knew the most’, the central consciousness of this novel whose understanding most closely approaches James's own. In his preface to the New York edition of The Spoils of Poynton, James explained that Fleda's ‘ingratiating stroke’ for him was that ‘she would understand’. Fleda refers to this understanding as ‘a kind of fourth dimension’, a particular choice of phrase that has not gone unnoticed in literary criticism. This is not Einstein's fourth dimension of space-time; Einstein's special theory of relativity was first published in 1905, and his general theory came six years later. In fact, Einstein's ideas did not begin to reach popular audiences until after their confirmation during the solar eclipse of 1919. To which fourth dimension does Fleda refer then, and how does an understanding of this idea contribute to our understanding of this text and others from the same period?

This book provides an answer to these questions by exploring the discourse of hyperspace philosophy and its position within the network of ‘new’ ideas at the end of the nineteenth century, before the rise of Einstein's popularity in the 1920s. Hyperspace philosophy grew out of the concept of a fourth spatial dimension, an idea that became increasingly debated amongst mathematicians, physicists and philosophers during the 1870s and 1880s in Britain and on the continent, as well as in the United States. English mathematician and hyperspace philosopher Charles Howard Hinton was the chief popularizer of the fourth dimension in Europe and North America and, from 1880 until his death in 1907, he published a number of literary, philosophical and mathematical texts on the subject. The influence of these texts, many of which were published as a series under the title of Scientific Romances, ranged surprisingly wide. The present study offers an extended examination of Hinton's work and – crucially – the influence of his ideas on contemporary writers and thinkers.