Page:Tom Swift and His Photo Telephone.djvu/167

Rh He was going to try to make the arrest of the man telephoning.

But for fear the scoundrel would go to a different instrument, Tom took another precaution. This was to have one of the operators in the central exchange on the watch. As soon as Mrs. Damon's house was in connection with another telephone, the location of the latter would be noted, and another private detective would be sent there. Thus Tom hoped to catch the man at the 'phone.

Meanwhile Tom listened to the hoarse voice at the other end of the wire, giving the directions to Mrs. Damon. Tom hoped that soon there would be an arrest made.

Meanwhile the talk was being faithfully recorded on the phonograph cylinder. And, as the man talked on, Tom became aware of a curious undercurrent of sound. It was a buzzing noise, that Tom knew did not come from the instrument itself. It was not the peculiar tapping, singing noise heard in a telephone receiver, caused by induced electrical currents, or by wire trouble.

"This is certainly different," mused Tom. He was trying to recall where he had heard the noise before. Sometimes it was faint, and then it would gradually increase, droning off