Glowing tubes full of gas proliferated--and gained scientific importance--in 1855, when glassblower Heinrich Geissler developed an improved vacuum pump. It was one of Geissler's tubes that Julius Plücker used when he first observed cathode rays in 1859.

Chicago Laboratory Supply and Scale Company. Catalogue of physical, chemical and biological apparatus: for use in laboratories of colleges, schools, and manufactories. Chicago: [1898?], p. 114.

1997- American Institute of Physics