Willis R. Whitney came to General Electric in 1900 to lead the company's new research laboratory. The lab, originally housed in a small shack behind the home of scientist Charles Steinmetz, grew into a major research institution by the time Whitney retired in 1932.

An early project for the new lab was to find a way to improve the incandescent lamp. For twenty years GE had been producing lamps made with a carbonized cellulose filament based on work done by England's Joseph Swan. While simple to operate, the energy-efficiency of these lamps was rather poor, a bit over 3 lumens per watt, and many inventors were working on designs that would emit more light for the same amount of power. Also, many of the initial patents granted to Edison had expired allowing commercial competition to grow.

The major competitive threat came from Europe where high energy costs motivated research into more efficient lamps. Lamps using metal filaments rather than carbon appeared on the market in 1898 and many additional devices were in development. Whitney began experimenting with the newly invented electric-resistance furnace -- carbonizing filaments at higher temperatures than had been previously possible.

He discovered that, when prepared at very high temperatures [give figure] carbon filaments took on metal-like properties. [this included a positive resistance characteristic]. By operating the filaments at higher temperatures than regular carbon filaments, Whitney could obtain higher efficiency while continuing to use existing production equipment. The new lamps were marketed in 1904 as "General Electric Metallized" or "GEM" lamps.

GEM lamps soon began replacing ordinary carbon lamps. While at 4 lumens per watt they were the most efficient carbon lamps made, the gain in efficiency was only minor compared to the 8 lumens per watt given by the first generation of tungsten filament lamps that were marketing in Europe that same year. Also, GE and other makers ultimately regretted their strategy of marketing the lamps as "efficient." Consumers became confused when GE's tungsten lamps became available in the early 1910s and were also sold as "efficient." By then customers were faced with buying expensive tungsten lamps, or cheaper GEM lamps -- both of which were touted as efficient. Whitney's GEM lamp was -- at the urging of lamp makers -- legislated out of existence during World War 1 as part of an effort to ration scarce raw materials.