Envelope containing spun glass.
This spun glass comes from a 14 drawer cabinet found in the Herschel family home in the 1950s. Collectively the contents of this and a similar cabinet seems to suggest that they were used by successive generations of the family to store specimens, material and apparatus for carrying out experiments. This spun glass was presumably used by John FW Herschel and/ or his children (it may even have been used by John FW with his children) as the raw materials for experiments.
National Maritime Museum, Greenwich, London, Herschel Collection