Yesterday I found the middle stake on the southern property line – the division between the two lots of Arthur's property here. Now from here, I should be able to use the same technique to find the southwestern stake, which was the original quest.
I had begun to worry I was an incompetent stake-locator. Therefore I am pleased that I succeeded in this task, and it gives me optimism for finding the next one – I know how to do it now, and I know the method I used works. Basically, I used string measured to the appropriate length, and a precision bearing, using a compass app in my smartphone.
[daily log: walking, 4km]