In "The Importance of Being Earnest", what does Jack have written on his calling card?what does jack have written on his card

"Mr Ernest Worthing, B.4 The Albany, W." is written on his cards.  Not only does Algy have one of them in the first act, he produces it to the Cecily's Merriman when he first arrives in the country.  He wants Cecily to think that he is the crazy and out of control brother of Jack.  So in Act I Algy reads it aloud, and in Act II Cecily reads it aloud.