Woodbury-type photograph by James Nasmyth from The Moon Considered as a Planet, a World, and a Satellite by James Nasmyth and James Carpenter. Reproduced by courtesy of the University Librarian and Director, The John Rylands Library, The University of Manchester.

The 'voice' in one of Emily Dickinson's poems urges its reader to 'Tell all the Truth but tell it slant - ': 'Success in Circuit lies'. It would have been impossible for the inventor James Nasmyth to have known Dickinson's verse, bound as it was in a tiny handmade fascicle hidden in a trunk at the end of her bed, but the book he produced with James Carpenter in 1874, The Moon Considered as a Planet, a World, and a Satellite, seems to have been touched by it.

Born into an artistic family in Edinburgh in 1808 and exhibiting considerable gifts as a draughtsman, Nasmyth became an engineering prodigy. Trained in London and Edinburgh, he came to Manchester, which was rapidly developing into a centre of engineering, in 1834. In 1839, at the Bridgewater Foundry in Patricroft, he invented the steam hammer and produced 'superlative machines of all sorts'. At the age of 48 he was able to retire and spend his fortune, time and talents pursuing his interests in astronomy and the new medium of photography.

The Moon Considered... provided the opportunity to indulge both passions at once. This odyssey in space delineates in minute, yet astronomical, detail the topography and geology of the moon as studied over a period of thirty years. Containing twenty-five plates produced by a panoply of illustrative processes, Nasmyth's lunar Baedeker also includes a number of lustrous Woodbury-type photographs of the moon.

Seeming to 'record as it looks', Nasmyth's camera appears to capture with 'mechanical fidelity' (Kelley Wilder) photographs of a 'non-symbolic objective character [which] leads whoever looks at them to see them not as images but as windows' (Vilém Flusser) onto a real and actual, silver-surfaced moon, convincing even to those eyes that postdate the missions of the Sputnik and Apollo eras.

Yet these photographs are not what they seem. It was technically possible to photograph the moon at this period, but it was not until the 1880s that materials were devised with the sensitivity to capture moonbeams and starlight. The clarity displayed in these portraits shimmers with a quality 'Too bright for our infirm Delight'.

Nasmyth outlines how he made 'careful drawings' of the moon 'when it was favourably presented through the telescope'. The drawings were repeated, revised and then reworked into exact plaster models. The models were 'placed in the sun's rays [to] faithfully reproduce lunar effects of light and shadow', then photographed. Through photography, with its dubious power to certify and authenticate, these complex constructions show the moon as 'most faithful representations of the original'.

Notwithstanding the devotion to empirical investigation that characterised nineteenth-century British science, Nasmyth appears to argue that we are closest to the 'Truth's Superb surprise' when we dwell in the possibility of fiction.

STELLA HALKYARD