The Ranken coach is a landau style horse-drawn vehicle brought to the Australian colony of New South Wales in the 1820s, and now held in the National Historical Collection of the National Museum of Australia. At some point, or points, in the vehicle's history the roof structure has been altered and parts of its original interior and exterior upholstery have been replaced with black coated fabrics resembling imitation leather. Three data sources were brought together to support the hypothesis that the alterations to the coach were made between 1923 and 1938. Two of these sources were historical research on the vehicle and research on materials used to simulate leather in the times when the coach was likely to have been altered. These were used to determine the likely dates for these changes, as well as the types of materials available at the time. The third source involved physical means of investigation to study the chemical composition of the coatings. These included visual inspection, Ultraviolet fluorescence evaluation, solubility tests, the diphenylamine spot test, Fourier transform infrared spectroscopy, and pyrolysis gas chromatography, mass spectroscopy. The hypothesis formed was that the fabric used for the new interior upholstery was probably coated with an alkyd-based formulation, and that the fabric used for the new roof coating was probably coated with a cellulose nitrate based formulation. One of the key findings of this research was that the composition of the alkyd-based material does not exactly mirror modern formulations. This could be due to age-related deterioration, to the lack of standardisation in early formulations, or the fact that at the period in question, it appears to have been common to mix concoctions at the point of application. The physical analyses also supported hints in the historical documentation that topical "varnishes" may have been applied separately over the coated fabrics to improve their appearance and weatherproofing.