"There are dark mists every way"
First hit on Google for "vector of the void" http://celestialweasel.livejournal.com/173235.html, the rest are scientific papers. Curiously last time I did the search, the Fritz Leiber story from which the phrase comes was one of the hits, now it isn't. On the other hand Alta Vista has it as a second hit http://www.gutenberg.org/files/23162/23162.txt Project Gutenberg thinks that the copyright wasn't renewed, so there it is.
""There's a storm in that vector of the Void."
"Circle it," Sid ordered.
"There are dark mists every way."
"Then pick the likeliest dark path!"
I called through the dark, "Fair is foul, and foul is fair, eh,
"Aye, chick," he answered me. "'Tis all the rule we have!""