HEAT LAMPE&MP 12.018 Electric Appliances & Apparatus no date
Silver ring on the "bullseye" type of heat lamp eliminates "heat spill" by bringing within the control of the reflector all heat rays except those that come directly down to the heating area. The result is that what were formerly spilled and wasted heat rays are now collected, reflected down to the heat area, and put to practical use for heating. see diagram 012.017 Original Caption by Science Service |