Working Geissler tube, c 1988.
© Science Museum / Science & Society Picture Library
In the mid 1850s, German glas blower Heinrich Geissler (1814-1879) produced the first permanently sealed discharge tubes, which were the forerunners of today's street lamps and neon lights. Two metal electrodes pass through the glass tubes, which contain rarified gases at low pressure. By passing high voltage electricity through the tubes, a coloured glow is produced, which varies in hue according to the gas used. Their first commercial application was at a light display for Queen Victoria's Diamond Jubilee in 1897.