I have been asked why a bust of George Barret junior should appear on the façade of the Royal Institute of Painters in Watercolour alongside Turner and Girtin.   The answer, I assume, is that he was nearly, but not quite, one of the founders of the Society of Painters in Watercolours, joining it after its first meeting in Stratford Coffee House in November 1804, was a devoted member, exhibiting local scenes of the Thames valley and home counties every year for thirty-eight years, and, perhaps most importantly, published The Theory and Practice of Water-Colour Painting Elucidated in a Series of Letters in 1840, so was regarded as a theoretician of the genre, helping to establish its currency.