As they continue through Newgate Prison, Wemmick tells Pip to “notice the man I shall shake hands with.” This should be easy, as Wemmick has not shaken hands with any prisoner so far.
Then he does shake hands with a man known as Colonel. This man served the King as a soldier! He says he thinks he will be getting out on Monday. (But Wemmick later, as they walk away, tells Pip that he will surely hang on Monday.) The Colonel is a pigeon-fancier and Wemmick makes a deal with him for two of his pigeons. They’re portable property, after all! (Wemmick’s favorite sort of item to collect.)