Who is Heinrich Geissler?
He was a German from a family of glass blowers in 1814. He worked with Julius Plucker one of his partners. He worked and tested on different tubes, pressures and gases. He soon discovered after lots of research that depending on the gas, the light color differed. Neon became red, Helium became gold, Argon became indigo and Krypton became grey-ish/white. He died 1879, right before the vacuum tube technology was created.
Then and Now
