Peter Cooper Hewitt became the inventor of the first fluorescent lamp when he was awarded a patent in 1901 for his low-pressure mercury vapor lamp. The first high-pressure mercury vapor lamp, invented by German-born Edmund Germer, Friedrich Meyer and Hans Spanner, was patented in 1927.
Peter Cooper Hewitt built upon the work of Julius Plucker and Heinrich Geissler, who applied electricity to tiny gas particles in a tube to create light. Hewitt created a bluish-green light with a mercury-filled tube. He teamed up with George Westinghouse to become the first team to manufacture it commercially. Thomas Edison applied for a patent in 1896, but his fluorescent light used X-rays to excite the atoms and never sold.