What were the terms of the codicil to the uncle's will in "One Thousand Dollars" by O. Henry?

A codicil is a legal document that alters the content of a will. It also serves to explain some aspects of the will in question.

In the story, Gillian was bequeathed one thousand dollars according to his deceased uncle’s will. The lawyers tell Gillian he is expected to report his spending of the sum as per the terms of the will. Gillian does not know how to spend the money and decides to give the money to Miss Hayden. Gillian claims a codicil was found that says Miss Hayden is to receive his additional one thousand dollars.

After giving his money to Miss Hayden, Gillian went to the lawyers to report his spending of the inheritance, at which point the lawyers reveal a real codicil. The codicil states that Gillian should receive an extra $50,000 if he spends his initial sum well but will forfeit the additional sum to Miss Hayden if he squanders the initial amount.