I was roaming the web today for one thing and found a stash of historical fire tower maps in Maine including the map used in the Bigelow Fire Tower from 1918 (Pre AT), also pre Flagstaff Lake and Dam. https://digitalmaine.com/do/search/?...4357321&facet= Its a large high resolution download (3.4 megabytes)
The hand drawn profile around the edge is quite a piece of work. I had a couple of copies of blueprint versions of the map for Mt Speck and carried it up to the fire tower one time. The profiles line up quite well. I figured they were probably all lost to history but many are on the same site.
For those not familar with the technology, the maps are specific to every firetower and is mounted on a circular table at the center of the tower. A sighting device called an Alidade https://en.wikipedia.org/wiki/Osborne_Fire_Finder is used to sight a source of smoke. The lettering is oriented so that the observer could read the text in the direction of the sight. The observer then called in by a crank type field phone or radio to a central office that then would take the shots from the different towers and determine the exact location by lining up the sight angles from multiple towers.