It occurred to me that the most obvious place to begin was with the hand written inscription inside the relay. It reads as follows:

“Capture of Fort Fisher, N.C.

1864. Presented by

Capt. Wm MacKintosh to his friend and comrade

Richd O’Brien

(unknown) S. Military Teleg

Dept. Va, & NC.

Who was Captain MacKintosh and the Military Telegraph? And what happened at Fort Fisher? Beyond those references I would include the key words “Richard O’Brien” and the “telegraph” and, starting with the easiest resource,  see what Google would turn up.

The first few things I found went a long way to fill in the picture. I didn’t find any references to Capt. MacKintosh. Yet. However, Richard’s name was mentioned in a book called “The Military Telegraph During The Civil War in the United States, With an Exposition of Ancient and Modern Means of Communication, and the Federal and Confederate Cipher Systems”  By William R. Plum. The references to Richard were seeded in three or four paragraphs spread throughout the book. It also mentioned a Fort but not Fort Fisher. It was Fort Monroe.