This telegraph line was owned by the Baltimore and Ohio Telegraph Company and extended from Boston to points south along the coast parareling an old (c.1850) railroad route. During pole line rebuilds of the 1890s-1920s the company used six-pin crossarms. These had steel pins with wooden cobs, just like the Western Union ones. Often, additional wires were placed on sidepins (I recall a scant few like this that remained in the 1970s). Shown is the line making its crossing over Water Street in Hingham, this pole employed a ten-pin crossarm.