"1861Z"^^ . "1861-05-05Z"^^ . . . . . . . "Peter Cooper Hewitt"@en . . . "Hewitt, Peter Cooper"@en . "1921Z"^^ . "American electrical engineer" . . "Peter Cooper Hewitt (May 5, 1861 \u2013 August 25, 1921) was an American electrical engineer and inventor, who invented the first mercury-vapor lamp in 1901. Hewitt was issued U.S. Patent 682,692 on September 17, 1901. In 1903, Hewitt created an improved version that possessed higher colour qualities which eventually found widespread industrial use."@en . . . "1921-08-25Z"^^ . .