1897 national electrical code
The very first official NEC book published
The very first official NEC book published
Class D Section 41 page 36 mentions there shall not be more than the equivalent of 4 quarter bends from outlet to outlet. In 1909 it changed to Shall not be more than 360 degrees in a run of conduit.
Section 48 on switches says that service switches "MUST" indicate whether the current is "ON" or "OFF"
I have (1) of these books