Roman Glass Research Project

This week I have finished sorting the residues from a single huge deposit of glass waste, selecting ever smaller fragments. The largest pile is naturally coloured blue-green vessel glass, which was collected for recycling, but I have found many more tiny fragments of glass thread, some less than 1mm in diameter. These were produced at various stages in the glass-working process, sometimes when testing the viscosity of the molten glass.

Strands and threads were also formed when a lump of hot glass, the gather, was removed from the furnace on the end of a blowing iron before it was inflated. Minute fragments fell on to the workshop floor and these are extremely fragile, which suggests that our dump of waste was from the working area itself.

When sorting out some colourless glass fragments I was very pleased to spot some distinctive glass with a fine crackle or crazing on the surface. This might be a faulty vessel, made in the workshop and thrown away, but it is too early to say yet – we shall have to look out for some more.

John and I have been looking at photos of modern glassblowers working in the Roman style with an experimental furnace, to see what sort of waste is produced by the various activities. This is a fascinating exercise and I am learning a lot. We hope to be able to classify our fragments by the production process to gain further insights into Roman glass-working techniques. Next week I shall begin the mammoth task of recording it all in greater detail.