Charles Day (May 15, 1879 – May 10, 1931)[1][2] was an American electrical, construction and consulting engineer, and co-founder of Day & Zimmermann. He is known as a specialist in public utility management and operation,[3] and for his seminal contributions to flow charts[4] and the routing diagram.[5]
^
George Valentine Massey (1968). The Mitchells and Days of Philadelphia: with their kin: Dr. S. Weir Mitchell and Helena Mary Langdon (Mitchell) and Kenneth MacKenzie Day, p. 11