The Ointment and the Evidence

The Mystery of The Invisible Dog

Jupiter Jones’s chemical marking trick begins as a way to reveal an invisible visitor and later becomes a means of identifying the ransom collector.

increasing

Bearing strength in each event

decreasing

A Chemical Recipe A Chemical Recipe from "The Mystery of The Invisible Dog". A Chemical Recipe A prepared mixture Jupiter Jones dissolves a metallic compound into water and mixes it with ointment.

A Chemical Recipe from "The Mystery of The Invisible Dog". A Chemical Recipe A prepared mixture Jupiter Jones dissolves a metallic compound into water and mixes it with ointment.

A Chemical Recipe A prepared mixture Jupiter Jones dissolves a metallic compound into water and mixes it with ointment. He expects the residue to react with skin and leave persistent black marks. A tool with limits The mixture is designed for ceramic handles, not every surface. Its purpose is not to catch a thief by itself but to turn contact into visible evidence.

Desk Handle Marks Desk Handle Marks from "The Mystery of The Invisible Dog". Desk Handle Marks A disturbed surface The desk handles are smeared, and an envelope has been moved.

Desk Handle Marks from "The Mystery of The Invisible Dog". Desk Handle Marks A disturbed surface The desk handles are smeared, and an envelope has been moved.

Desk Handle Marks A disturbed surface The desk handles are smeared, and an envelope has been moved. Jupiter Jones concludes that someone entered and touched the drawers while the boys were away. A solved intrusion The marks lead to Mrs Bortz and her duplicate key. The test separates a human snooper from Prentice’s fear of an immaterial shadow.

The Ransom Decoy The Ransom Decoy from "The Mystery of The Invisible Dog". The Ransom Decoy Fake money prepared Jupiter Jones cuts newspaper into bill-sized rectangles and treats them with the same ointment.

The Ransom Decoy from "The Mystery of The Invisible Dog". The Ransom Decoy Fake money prepared Jupiter Jones cuts newspaper into bill-sized rectangles and treats them with the same ointment.

The Ransom Decoy Fake money prepared Jupiter Jones cuts newspaper into bill-sized rectangles and treats them with the same ointment. He wraps them in brown paper so the parcel looks plausible. A second use The technique that exposed a snooper now links the apartment mystery to the theft. Whoever handles the parcel may carry evidence back to a hiding place.

The False Collector The False Collector from "The Mystery of The Invisible Dog". The False Collector A marked package taken A ragged man lifts the parcel from the bin and escapes through the street.

The False Collector from "The Mystery of The Invisible Dog". The False Collector A marked package taken A ragged man lifts the parcel from the bin and escapes through the street.

The False Collector A marked package taken A ragged man lifts the parcel from the bin and escapes through the street. The ointment plan does not immediately deliver the culprit to the police. A useful failure Jupiter Jones treats the escape as information: the runner is not the man who can safely claim the money. The evidence method remains useful because it sharpens the next deduction.

The Hands Exposed The Hands Exposed from "The Mystery of The Invisible Dog". The Hands Exposed A trail to the clinic Jupiter Jones predicts that the real burglar remains in the hospital and directs officers to Murphy’s room.

The Hands Exposed from "The Mystery of The Invisible Dog". The Hands Exposed A trail to the clinic Jupiter Jones predicts that the real burglar remains in the hospital and directs officers to Murphy’s room.

The Hands Exposed A trail to the clinic Jupiter Jones predicts that the real burglar remains in the hospital and directs officers to Murphy’s room. The decoy parcel and treated surfaces have helped make the plan testable. Evidence joined to logic The arrest depends on more than black marks: the package, the alibi, and the timing converge. A small invention supports a larger chain of reasoning.

Before sunrise after the first interview

Late morning after the ointment is applied

The morning the ransom letter arrives

Five o’clock at Paseo Place Park

Minutes after the park handoff