The electric motor, the telegraph, and Joseph Henry´s theory of technological progress

Joseph Henry (1797-1878), America´s foremost electrical physicist of the early nineteenth century, stood at the center of the developing science and technology of the newly discovered electric current. The electromagnetic telegraph and the battery-powered motor were two leading technological efforts of the period. Although Henry chose not to engage in the actual inventive process, he closely followed the development of both devices. While he fully supported the work on the telegraph, especially S.F.B. Morse´s experiments, he stood opposed to the battery-powered motor on the grounds of impracticality. He stated these views forcefully to the numorous inventors who sought his expert advice on electricity. This paper explores the reasons for Henry´s contrasting opinions of the telegraph and the motor. Underlying these opinions was a set of assumptions about the progress of technology and its proper relations to scientific knowledge and the current needs of society.