Composing room lit by
Cooper Hewitt lamps
composing room lit by Cooper Hewitt lamps
Peter Cooper Hewitt constructed the first
practical applicable arc discharge lamp in
1901. The greenish-blue colour of this
low-pressure mercury vapour arc
discharge lamp limited its use for lighting
purposes. The relatively high amount of
emitted ultraviolet radiation however,
made the lamp suitable for treatment of
certain skin diseases. For therapeutic
applications, high-pressure mercury
vapour arc discharge lamps have proven
to be the most effective. In order to avoid
the bulb of such lamps from melting, their
temperature and thus their effectiveness
had to be limited. Küch and Retschinsky,
the former closely related to Heraeus (Hanau, Germany), solved this problem in 1906
with the use of quartz glass. This quartz glass had a melting temperature of about
1100 degrees Celsius instead of somewhere between 500 and 800 degrees Celsius
like conventional glass.