Society of Glass Technology · [Sheffield] · leaf 661
formed around the lower end of the electrode and the tips of theglass core fire polished. The plug comprises a central electrode, 1, a core, 2, of lower-expansion borosilicate glass, moulded around the electrode andinside of a metallic band, 3, and a shell member, 4, into which theband screws. The…
Glass
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten15unit-945-498.webp)
