Edgar B. Mangam is listed in the New York City Directory, beginning in 1869, as "Edgar B, grain, 92 Broad, 16 Stone & 438 E 23d, h B'klyn." Listed at the same business address are Sylvester S. Mangam, feed, and Stephen J. Mangam, grain, both with a home address of 327 E. 17th St. There is also a listing for W.D. Mangam Sons, grain, 92 Broad & 438 E 23d. In 1870 a listing was added for Mangam & McCord, mers, 16 Stone. In 1871, Edgar's home address was given as 140 Wash. Av B'klyn. In 1873, it changed to 216 Wash. Av B'klyn. In 1881, his business address was given as 92 Broad & elevators, Pier 6 NR. In 1884, his addresses were 442 Produce Ex, h 227 Wash Av B'klyn. In 1910, the business address changed to 90 Broad Mhtn. Between 1869 and 1910, in addition to the names quoted above, there were numerous other individuals and businesses shown with the name Mangam.