Circa 1920 100rs blue, 300rs green, 1000rs brown, 2000rs red, 5000rs violet blue, 10,000rs deep red, 20,000rs green and 50,000rs violet 'Estado de Para - Thesouro' REVENUE issue, the set of eight WATERLOW COLOUR TRIALS printed by lithography, perforated on gummed paper each stamp with small hole punch. Very scarce. (Barata #56/59 & unlisted)