By the 1970s, there were good designs for smaller furnaces, and in the United States this
gave rise to the"studio glass" movement of Glassblowers, who worked outside of factories, often in their own buildings or studios.
In the 19th century, two Germans- glassblower Heinrich Geissler and physician Julius Plücker-
discovered that they could produce light by removing almost all of the air from a long glass tube and passing an electrical current through it, an invention that became known as the Geissler tube.