The foresters I flew carried their Silva Rangers exactly the same way. They could start at a corner survey post on a section of land, run through the bush a mile to another corner and find the original survey post, set many years previous, using just a steel tape two chains long, plus the tail with allowance for difference in elevation over the length of the tape, and usually find the old post, usually a wooden post that had rotted away, in about 10 to 15 minutes. The lead man would sight with his Silva and when he got the picture, he would drop the compass on its cord and not take his eyes from the spot he was going to. He would make a mark in the ground with his foot where he took the sight from. The chain man would be following the end of the chain and when it reached the mark in the ground he would yell "Chain,' or some variant. The lead man had the chain fastened to his belt and when he heard the call, would stop, face back to the chain man, snug the tape up and take a reading on the face of the chain man with his instrument, showing the difference from level, call out the figure and then slowly move until the chainman called and they then new they here exactly two chains apart, regardless how much higher or lower the men were from each other.
A chain is 66 feet long, so 80 chains made 5280 feet, one mile.
Wow, I didn't know this would be so long, but once I started, intending to show how accurate sighting a Silva Ranger compass, I just had to give details, or it wouldn't have made sense, or someone would say, "That's not the way they did it!"
Bruce