Metals were vital to Thomas Edison, from iron, copper, and various alloys used in new inventions to gold for plating phonograph record molds, and in the metallurgical laboratory workers collected, assayed, and evaluated the metals used for his projects. In the 1890s Edison employees experimented with the magnetic extraction of iron from low-grade ore, but by 1900 the discovery of high-grade ore deposits dashed his hopes of making a profit from milling New Jersey’s low-grade ores. After losing millions, Edison said, “Well, it’s all gone, but we had a . . . good time spending it!” Later, Building 4 was put to non-metallurgical uses, with experiments in sound recording and phonograph record supplication conducted there before 1903, and by 1912 much of the experimental work concentrated on the diamond disc phonograph.
