A German physicist, born at Breslau on September 26, 1856, Graetz studied mathematics and physics at Breslau, Berlin and Strassburg. In 1881 he became assistant to A. Kundt at Strassburg and in 1883 he went to the University of München, where he became professor in 1908 and occupied the second chair for physics in parallel to Roentgen.
His scientific work was first concerned with the fields of heat conduction, radiation, friction and elasticity and after 1890 with problems of electromagnetic waves and cathode rays.
Graetz was a prolific technical writer, with 23 editions of his Electricity and its Applications and a five-volume work, Handbook of Electricity and Magnetism, which contributed to the wide dissemination of knowledge in electricity, which at that time was in its infancy. He died in München on November 12. 1941.