 Complete the following phrase:  Apart from his work at the British Museum, Doubleday was a dealer and a copyist of coins, medals, and ancient seals. He sold sulphur and white metal casts, the former coloured in different hues, at his establishment, which, located near the British Museum, may have helped facilitate his employment there. He also sold curiosities, such as cabinets, snuff boxes, and lead seals purportedly made from materials taken from the 