Johann Heinrich Wilhelm Geißler (26 May 1814 in Igelshieb – 24 January 1879) was a skilled glassblower and physicist, famous for his invention of the hand pumped Geissler mercury vacuum pump in the mid-1850's and in 1857, the Geissler tube, made of glass and used as a low pressure gas-discharge tube; these two inventions were critical technologies leading to the discovery of the electron.

Geissler descended from a long line of craftsmen in the Thüringer Wald and in Bohemia.

There he was asked by physicist Julius Plücker to design an apparatus for evacuating a glass tube.

Plücker owed his forthcoming success in the electric discharge experiments in large measure to his instrument maker, the skilled glassblower and mechanic Johann Heinrich Wilhelm Geissler.

[3]The Geissler tube was used for entertainment throughout the 1800s and evolved around 1910 into commercial neon lighting.