Because a firm named General Instrument already existed, the company was renamed Texas Instruments that same year. From 1956 to 1961, Fred Agnich of Dallas, later a Republican member of the Texas House of Representatives, was the Texas Instruments president. Geophysical Service, Inc. became a subsidiary of Texas Instruments. Early in 1988, most of GSI was sold to the Halliburton Company. Geophysical Service Incorporated In 1930, J. Clarence Karcher and Eugene McDermott founded Geophysical Service, an early provider of seismic exploration services to the petroleum industry. In 1939, the company reorganized as Coronado Corp, an oil company with Geophysical Service Inc (GSI), now as a subsidiary. On December 6, 1941, McDermott along with three other GSI employees, J. Erik Jonsson, Cecil H. Green, and H. B. Peacock purchased GSI. During World War II, GSI expanded its services to include electronics for the U.S. Army, Army Signal Corps, and U.S. Navy. In 1951, the company changed its name to Texas Instruments, spun off to build seismographs for oil explorations and with GSI becoming a wholly owned subsidiary of the new company. An early success story for TI-GSI came in 1965 when GSI was able (under a Top Secret government contract) to monitor the Soviet Union's underground nuclear weapons testing under the ocean in Vela Uniform, a subset of Project Vela, to verify compliance of the Partial Nuclear Test Ban Treaty. Texas Instruments also continued to manufacture equipment for use in the seismic industry, and GSI continued to provide seismic services. After selling (and repurchasing) GSI, TI finally sold the company to Halliburton in 1988, after which sale GSI ceased to exist as a separate entity. Semiconductors In early 1952, Texas Instruments purchased a patent license to produce germanium transistors from Western Electric, the manufacturing arm of AT&T, for $25,000, beginning production by the end of the year. Haggerty brought Gordon Teal to the company due to his expertise in growing semiconductor crystals while at Bell Telephone Laboratories. Teal's first assignment was to direct TI's research laboratory. At the end of 1952, Texas Instruments announced that it had expanded to 2,000 employees and $17 million in sales. Among his new hires was Willis Adcock, who joined TI early in 1953. Adcock, who like Teal was a physical chemist, began leading a small research group focused on the task of fabricating grown-junction, silicon, single-crystal, small-signal transistors. Adcock later became the first TI Principal