The Sphynx Without A Secret

Murchison saw the woman in the photo at Bond St. This implies that he recognized the woman in the photo and encountered her in person. It is possible that he had been searching for her or had some prior connection with her, leading to their meeting at Bond St.

The name of the woman is Lady Alroy.

Gerald Murchison is identified as an old university friend based on the given options. This suggests that the person in question has a connection with Gerald Murchison from their time in university. The other options, such as one of his brothers, an old school friend, or his neighbor, are not mentioned in the explanation, indicating that they are not the correct answer.

The action takes place in Paris.

The correct answer is A handkerchief. This is indicated by the phrase "drop at Cummor Street." Since a handkerchief is an item that can easily be dropped or misplaced, it is the most likely object to be dropped in a street.

The woman being referred to in the question is described as a widow. This means that her husband has passed away and she is no longer married. Being a widow implies that she was previously married but is now single due to the death of her spouse.

The correct answer is "In a house in Park Lane." This answer suggests that she lived in a regular house rather than a flat, attic, or semi-detached house. Park Lane is a well-known street, so it is plausible that she lived in a house there.

Murchison took out a photo of a tall woman from his pocket.

Murchison had a date with the woman at half past four. This means that the time was 4:30.

Green Street was a poor district of London. This can be inferred from the fact that it is described as "poor" in the given options.