The new TV series "The Alienist" is set in 1896 New York. In the beginning of the first episode a policeman, walking alone,discovers a murdered and mutilated boy in the snow. To summon help he goes to the nearest metal pole and bangs on it repeatedly with his stick. Someone else hears the signal and begins hitting his own object. The signal is relayed in this manner until the whole city is full of rhythmic noise from people hitting various objects to forward on the signal. Is any of this accurate? Is this the way emergency signals were related at that time? If not, how was it done?
"Prior to the ability of NYC foot patrolmen to receive information from either headquarters or their precinct, a citizen requiring immediate help needed to find the beat officer, or appear in person at a local precinct to report a crime or call for assistance. Likewise, officers on a beat relied on the rapping of their hardwood nightsticks against a curb, or blowing their cylindrical-style police whistles to summon aid from officers on adjoining posts. Police commanders needed to have their messages and orders communicated by hand delivery to all local precincts. The delays in communication resulted in loss of life and property, decreased efficiency in administration and inability to contact patrolmen. The benefits derived by the fire services use of the telegraph served as one of the justifications for the PD to adopt the system."