New York: Van Nostrand, 1903. First Edition. hardcover. 41 illus. 72pp. + ads. Thin 8vo, orig. gilt-lettered cloth. New York: Van Nostrand, 1903. First Edition. Very good (+). very good(+).
Inscribed by the author. Hammer was an assistant to Thomas Edison and responsible for tests and records on incandescent lamps, later chief engineer of the Boston Edison Company and Edison's personal representative to the Paris Exposition of 1889. DAB.