At the age of twelve, Hammond accompanied his father on a business trip to Thomas Edison’s laboratory in West Orange, New Jersey. Upon being introduced to Edison, the boy asked so many questions that the inventor gave him a personal tour of the complex and assumed the role of mentor. The two would remain in contact for the rest of Edison’s life. While studying at the Sheffield Scientific School of Yale University, Hammond became interested in the new study of radio waves and he was taken under the wing of Alexander Graham Bell. Bell also became his mentor and the two would remain close friends until Bell’s death.