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
illumination 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.