What was Mr. White's third wish? How do you know that it came true?

This question is about the short story "The Monkey's Paw," by W. W. Jacobs.

Answer and Explanation:

Mr. White and his family are visited by a friend, a sergeant, who has been to India, where he obtained a mummified monkey's paw. According to him, the paw has been enchanted by a fakir and it can grant three wishes to three different people. He says he has already used his, and that another man has also used his wishes, the last wish being for his own death. He warns the Whites that paw is dangerous, and that its purpose is to show we should not interfere with fate.

Mr. White's first wish is for 200 pounds to pay a debt. He does receive the money, but only because he son dies in an accident at the factory where he works. Devastated, Mrs. White demands that her husband wish for their son to return. He eventually concedes and makes the wish. They soon begin to hear someone insistently knocking at their door.

Mr. White is sure it is their son outside. However, he does not want his wife to see his maimed body - their son's body was caught in a machinery at work. Desperate, he grabs the paw and makes a third wish.

What was Mr. White's third wish? How do you know that it came true?

The narrator does not tell us what the wish was, but we can infer it from the context. Once Mr. White makes the wish, the knocking stops, and they open the door to find a deserted street. We can safely assume he wished for his son to go away, probably forever. And we know it came true because the knocking stops quickly afterwards and, even though the couple rushes to the door, there is no one outside. If it were just a a visitor or a passerby, he would have had no time to disappear like that.