Scanning our past from London: Fluorescent lighting

The electric light most commonly found in shops and offices, and increasingly in the home, is the fluorescent tube, available in many shapes, sizes, and colors. These exploit a gas discharge. The discharge is mercury at low pressure, together with a little argon or krypton to help with starting. It produces a blue light as in the early mercury discharge lamps, but that is not what is used. The fluorescent lamp exploits the much stronger UV light that is also produced. A phosphor coating on the inside of the glass tube converts this UV into visible light. The glass, which is ordinary soda glass, is opaque to UV light so none escapes. The development of the fluorescent lamp based on the work of George Stokes and Alexandre Edmond Becquerel is discussed. The the use of more efficient phosphors and the development of slimline fluorescent tubes and compact fluorescent lamps are also briefly mentioned.