Clays soon took his place among the most famous Belgian painters of his generation, and his pictures, sold at high prices, are to be seen in most public and private galleries. We may mention, among others, "The Beach at Ault", "Boats in a Dutch Port", and "Dutch Boats in the Flushing Roads", the last in the National Gallery, London. In the Brussels gallery are "The Port of Antwerp", "Coast near Ostend", and a "Calm on the Scheldt"; in the Antwerp museum, "The Meuse at Dordrecht"; in the Pinakothek at Munich, "The Open North Sea"; in the Metropolitan Museum of Art, New York, "The Festival of the Freedom of the Scheldt at Antwerp in 1863"; in the palace of the king of the Belgians, "Arrival of Queen Victoria at Ostend in 1857"; in the Bruges academy, "Port of Feirugudo, Portugal". Clays was a member of several Academies, Belgian and foreign, and of the Order of Leopold (Belgium), the Legion of Honour, etc. See Camille Lemonnier, "Histoire des Beaux-Arts" (Brussels, 1887).