History of Science

Origin of vacuum tube + electricity experiments#

After the invention of the vacuum pump in 1654 by Otto von Guericke, physicists began to experiment with passing high voltage electricity through rarefied air. In 1705, it was noted that electrostatic generator sparks travel a longer distance through low pressure air than through atmospheric pressure air.

why the heck did people try to pass high voltage electricity through rarefied air, and what's the concepts they had when they're dealing with this class of experiments? - they certainly didn't know what's "voltage".