Discussions of temporality in Romantic literature generally distinguish between objective forms of time-telling (clock time) and subjective varieties (psychological time). Although critics have tended to neglect the former, perceiving it to be ‘boringly numerical’ and the ‘lowest’ form of horology, the present article examines the complexities of practical time-telling from a broadly ecocritical perspective, arguing that, far from being a tedious embodiment of cold systematic regularity, the maddening untrustworthiness of clocks and watches ensured that time-telling was an unavoidably relativistic activity which caused frequent frustration, anxiety, and confusion throughout the period. By the late eighteenth century, apparent solar time (so-called ‘sundial time’) was gradually being superseded by mean solar time, and, even though the latter potentially offered greater regularity, the calculation of the mean itself varied depending upon the meridian used. Greenwich Mean Time, determined from the prime meridian in Greenwich, was adopted by the Railway Clearing House in 1847, eventually becoming the standard time zone for Great Britain in 1880, and a world standard in 1884. However, during the period 1780 to 1830, these distinct systems were all in common use simultaneously, and the periodicals’ letters pages regularly contained proposals for a unified system. In 1829, J. Utting prophesied that ‘the time is not far distant when mean solar time will be adopted, in nautical astronomy in particular, to the complete exclusion of apparent time’. Paul Glennie and Nigel Thrift have recently examined how these various systems were deployed, and they have boldly concluded that ‘[. . . ] there is no such thing as clock time. Rather clock time comprises a number of concepts, devices, and practices which have meant different things at different times and places, and even in any one place have not had a unitary meaning’. So far, sundials have not featured prominently in such reappraisals, yet, as time-telling devices, they fuse ecological and horological concerns in a distinctive manner. Since the early 1990s, ecocriticism has repeatedly sought to ‘collapse the artificial distinctions between nature and culture’, and Ashton Nichols has recently destabilised this dichotomy even further by focusing on ‘urbaniture’, a domain in which the natural and the urban are ‘linked in a complex web of interdependent interrelatedness’. Sundials do not impose upon or coerce nature; rather, they inertly display the diurnal regularities that are manifest as the earth spins on its axis while orbiting the sun. By contrast, mechanical timepieces tried to be consistent with the