"I've forgotten it, Chief. That spot drove it all out. No, wait--say! I've been thinking--this morning laying there and listening to the kids getting ready for school--that the powder we smelled in the library wasn't ordinary powder. I know a firecracker, or a regular Chinese smell when I get near one. That wasn't the kind I got. It was like something else. It was powder--all right--but----" Drew lifted a sheet of paper. "I covered that," he said. "Analysis made by Higgens, this morning, shows traces of smokeless-powder in Stockbridge's hair and about the bullet hole. There's a difference. Now, I'm going further than that. I'm going to have those scrapings I got from my neck looked at. If they are the same as the powder that was used to slay Stockbridge, we are getting on." "There's lots of smokeless, Chief." "That's the trouble--that's what we are right up against. Let's leave the footprints and the powder for a few minutes. Both are important. They'll wait. See here!" Drew raised a sheath of papers from his desk, turned with the chair, and started thumbing over the data he had accumulated. "See here," he repeated absently. "First branch of the tree of Truth in this case is a stubborn one. It requires considerable work on our part to get to the end of it. I've sent out six operatives to scout the telephone calls and get me some light on them. I've kept some notes on what they have 'phoned in to me. The telephone company, the wire-chief at Gramercy Hill, and an official I know, have been enlisted in getting to the bottom of these calls. They have made progress. But, Delaney, of all the devilish inventions of man, a telephone is the most subtle. It's a wonder to me we have found anything. It's the crook's one best tool. With it he can play safe, and we can't catch him!" "What have you found, Chief?" Drew held up a paper. "The first call, Delaney," he said, "was the one to the cemetery company's superintendent, notifying him to excavate a grave in the Stockbridges' family plot. Subtle suggestion, that, in the light of what followed." "It was," said Delaney. "This call has received all of the attention it deserved. It's the first of the series, and was perhaps made before the crook had time to cover himself completely. It has been traced to a slot booth in the Pennsylvania Railroad Station in the Woman's Waiting Room." "Woman's?" "Yes, Delaney. That is no criterion that a woman did the calling-up. The girl there in charge of the pay-booths states that more men than women use the 'phones in that part of the station." "Just our luck!" "The toll collected on this call must have been thirty-five cents, including the war-tax. The superintendent says that the voice over the wire was thin and tired. He says he thought it was Dr. Conroy. He never gave the matter second consideration. Conroy, however, has a voice like a bull. We checked that up." "Does the superintendent know Conroy?" "No! Except by name!"