What is the meaning of the title to part 2 (The Sieve and the Sand)? Why do you think so?

There are two meanings here. One involves Montag's childhood memory. His cousin challenged him to fill a sieve with sand in exchange for a dime. Of course the sand keeps falling through which causes young Montag to cry. The other incident involves Montag's attempts to memorize the Book of Ecclesiastes from the Bible, but the moronic jingle from the advertisement for Denham's Dentifrice that keeps playing while Montag is trying to disseminate the words to the Bible. His thoughts keep falling out like sand through a sieve.