William Coolidge, born #OTD in 1873, was elected to the National Inventors Hall of Fame in 1975 at the age of 101. He was an American engineer and physical chemist who made major contributions to incandescent bulbs and x-ray machines. . . . . . . . . #chemist #xray #engineer #stem #chemistry #science #scientist #halloffame #history #sciencehistory #education #learn #scienceclass #invention #inventor