This Phil thought was the appropriate time to get close to the cab, and clambering back to the top of the car made his precarious way along the tops of the string. The pelting rain soaked him to the skin, and in addition made the walking perilous, for the boards became almost as slippery as glass.

When he came within two cars of the engine, he dropped to his hands and knees, and crawled, animal fashion, along the top. The rain and the darkness still continued, and as he neared the end of the last car, he laid flat and wriggled along until he came to the edge.

From his perch he could see down into the cab of the engine, across the small coal tender. He could see the engineer and Simmons engaged in an animated conversation, but the rush of the train and the noise of the rain made it impossible to hear what they were saying.

He could see perfectly, by the light from the open engine boiler door, all that was transpiring, and what he saw gave him the solution to the mystery of the missing letters.

Simmons had taken a small tool of some sort from his pocket and was engaged in picking the lock of the registered mail bag.

He made short work of this, and then ensued a strange scene.

The engineer worked a small pet-cock that let out a thin stream of hot steam, and passing the letters back and forth over this, Simmons opened them. That is, he opened several that he had selected, after a hasty glance at the superscription.

From the envelopes, he took out some of the contents, and then moistening the glue again with steam, carefully pressed them back. This process is often used by culprits, but it speaks well for the law that few of them get very far with it, for Uncle Sam safeguards his mails with an eternal vigilance.

To Phil it appeared that the postal inspector was either an out and out criminal, who had successfully blinded the postoffice department to his criminal ways, or had for some reason succumbed to temptation. Later he was to learn what the real reason was.

Phil was wondering what his next step had better be,—to go back and seek the safety of the space between two cars and ride to Coldenham and there get into connection with Ferguson and have the pair arrested, or to try and drop off just before they struck the town and get some conveyance to take him back to Hobart, where he could confer with Dick and possibly arrange to see how far Simmons would go.