simply rubbed an evacuated glass globe which could be rapidly
spun on an axle by a "great wheel". Inside the globe
was Hg. One of the axles was hollow, and connected to the globe through
a valve. He connected it to a vacuum-pump, and sucked all
the air out. When he spun the device in the dark,
rubbing it with his bare hand - behold, there was a glow. This
event occurred in 1705.
he had made a light source bright enough that "... Words in Capital
Letters were legible by it".