In the latter half of the 19th century, Gustave Pierre Trouve, a modest but brilliant Parisian electrical engineer, conceived and patented some 75 inventions, including the endoscope, the electric car and the frontal headlamp. He also designed an electric boat--complete with outboard motor, headlight and horn--an electric rifle, an electric piano and luminous fountains, and developed wearable technology and ultraviolet light therapy. Unlike...