Het spiegelende koetje: a milkmaid conversing with a peasant by a farmhouse, with cattle watering and sheep and goats by a tree, swimmers beyond

The prototype, signed and dated 1648, oil on panel, 43.3 x 61.3 cm, is in the Mauritshuis, The Hague (A. Walsh, E. Buijsen & B. Broos, Paulus Potter, exhibition catalogue, Mauritshuis The Hague, 8 November - 5 February 1995, p.95, no.14, ill.). It was the superb rendering of the reflection of the cow in the foreground in the water, that had given the painting its title by the end of the eighteenth Century. Already in 1781, Sir Joshua Reynolds expressed his admiration for this feature: 'Cattle, finely painted by Potter, remarkable for the strong reflection of one of them in the water' (E. Buijsen, loc. cit.).