“Only with a key. That will give no trouble at all,” said the man. He proved it by opening it with the third key he tried from a bunch of many he took from his valise.
That was all there was for him to do, save to set the combination with a simpler system, which he did, giving Viola the numbers.
“Was it as easy as you thought?” she asked, when the expert was about to leave.
“Not quite—no. The combination was a double one. That is, in two parts. First the one had to be disposed of, and then the other worked.”
“Why was that?”
“Well, it is on the same principle as the safe deposit boxes in a bank. The depositor has one key, and the bank the other. The box cannot be opened by either party alone. Both keys must be used. That insures that no one person alone can get into the box. It was the same way with this safe. The combination was in two parts.”
“And did my father set it that way?”
“He must have done so, or had some one arrange the combination for him.”
“Then he—he must have shared the combination with some one else!” There was fright in Viola's eyes, and a catch in her voice.
“Yes,” assented the expert. “Either that or he set it that way merely for what we might call a 'bluff,' to throw any casual intruder off the track. Your father might have possessed both combinations himself.”