And Darwin after the break.
In both these cases, we have a lead word that captures most of the movement, and then one or two follower words below that check in decade later and then fairly well track the main word's movement. I'd have to plot them normalized to be sure, but I think my similarity functions would notice the similar curves here. The only worry I have is that "Darwin" has a baseline of about 50, which might make the function think that it's very different from the derived adjectives. (It is different, of course, but short of running a script to get the data for "Charles Darwin", which I remain loathe to do, there's no way to exclude the references in there to Erasmus, the Australian city, etc.).