"[...] but, as a rule, I like to be alone and undisturbed." (2.13)
Just to make sure we understand, the Invisible Man comes right out and tells us that he prefers to be alone.
"I was alone…In all my great moments I have been alone." (19.37)
At the beginning of his talk with Kemp, the Invisible Man makes a connection between being alone and being awesome. We'll see if he keeps this opinion for the rest of the book. (Spoiler alert: he doesn't. Check out the last quote in this theme.)
"[...] a footprint as isolated and incomprehensible to them as Crusoe's solitary discovery." (21.15)
You know how in alien invasion movies, someone always says, "we're not alone"? We imagine the London urchins might feel something equally strange (and awe-inspiring) when they see this footprint that they can't explain. (Check out the "Allusions" for more on the Robinson Crusoe.)