• Glass is made from a mixture of common chemicals: silica, lime and soda or potash. These chemicals are dried and then heated together, a process known as fritting.

• The frit is then placed in pots in a chamber above the furnace. The heat melts the frit to produce glass.

• Once the bottles etc had been blown they then had to be cooled very slowly (annealed) to stop them cracking.

It was then converted into a pottery kiln, with the floor level being raised and small pottery kilns being built inside during the 19th century. In about 1870 a railway siding was built to connect the pottery with the docks.

The Glass Cone was last used in 1939. It was demolished in 1943, excavated 1975-76, and consolidated in 1985.