With another deferential bow, the clerk hastened to display a case of watches and they bent over them.  As each new watch was pointed out, Elaine was delighted.

Unobserved, the crook walked over near enough to hear what was going on.

At last, with much banter and yet care, Elaine selected one that was indeed a beauty and was about to snap it on her dainty wrist, when the clerk interrupted.

“I beg pardon,” he suggested, “but I’d advise you to leave it to be regulated, if you please.”

“Yes, indeed,” chimed in Susie.  “Father always advises that.”

Reluctantly, Elaine handed it over to the clerk.

“Oh, thank you, ever so much, Mr. Bennett,” she said as he unobtrusively paid for the watch and gave the address to which it was to be sent when ready.

A moment later they went out and entered the car again.

As they did so, Spike, who had been looking various things in the next case over as if undecided, came up to the watch counter.

“I’m making a present,” he remarked confidentially to the clerk.  “How about those bracelet watches?”

The clerk pulled out some of the cheaper ones.

“No,” he said thoughtfully, pointing out a tray in the show case, “something like those.”

He ended by picking out one identically like that which Elaine had selected, and started to pay for it.

“Better have it regulated,” repeated the clerk.

“No,” he objected hastily, shaking his head and paying the money quickly.  “It’s a present—­and I want it tonight.”

He took the watch and left the store hurriedly.

. . . . . . . .

In the laboratory, Kennedy was working over an oblong oak box, perhaps eighteen inches in length and half as high.  In the box I could see, besides other apparatus, two good sized spools of fine wire.

“What’s all that?” I asked inquisitively.

“Another of the new instruments that scientific detectives use,” he responded, scarcely looking up, “a little magnetic wizard, the telegraphone.”

“Which is?” I prompted.

“Something we detectives might use to take down and ‘can’ telephone and other conversations.  When it is attached properly to a telephone, it records everything that is said over the wire.”

“How does it work?” I asked, much mystified.

“Well, it is based on an entirely new principle, in every way different from the phonograph,” he explained.  “As you can see there are no discs or cylinders, but these spools of extremely fine steel wire.  The record is not made mechanically on a cylinder, but electromagnetically on this wire.”

“How?” I asked, almost incredulously.

“To put it briefly,” he went on, “small portions of magnetism, as it were, are imparted to fractions of the steel wire as it passes between two carbon electric magnets.  Each impression represents a sound wave.  There is no apparent difference in the wire, yet each particle of steel undergoes an electromagnetic transformation by which the sound is indelibly imprinted on it.”