4 Slichter's leadership of electrical engineering lasted until 1941. This era spanned the First World War and the emergence of radio as a communications and entertainment vehicle. The electrification of New York City was completed, and electrically powered industries dominated manufacturing. During the First World War the department played a critical role in giving the United States first-rate electrical technology. Virtually the entire department volunteered to teach at the Navy Submarine School in New London, Conn. Both Crocker and Pupin were senior consultants. Later, Armstrong played a critical role in bringing radio communications to the U.S. Army in France.
Throughout the Slichter era, the department evolved along two dominant technical tracks: electrical motors and power, and radio. Morton Arendt and Slichter, who trained at General Electric under the legendary Charles Steinmetz, were masters of the art of designing and engineering electrical motors, and perhaps could be viewed as Crocker's successors. In radio communications, Armstrong and Morecroft were the dominant forces. Armstrong was the inventor par excellence, but it was Morecroft who first put the technology of radio on paper. In 1921, Morecroft published his groundbreaking book, The Principles of Radio Communications. Clearly, this area of departmental interest can be traced directly to Pupin's deep involvement in electrodynamics. During World War Two, when mobile military communications made effective use of Armstrong's FM system, many students in the Navy V-12 program were taught by electrical engineering faculty, including Arendt, whose inventions over a long, productive career included variable-speed commutating pole DC motors, storage batteries and other components used in modern diesel-electric submarine vessels.