In his hand Jack held the flashlight "gun." It was one of those patent affairs, arranged to fire a charge of magnesium powder by the explosion of a cap when the trigger was pressed.

Dropping to one knee, Hal set the camera, half by instinct, half by guess. While he did so, Jack fixed a charge of the powder in the firing pan of the "gun."

These preparations made hardly any noise; such as might have been heard in a silent room was drowned by the tap-tap of a small hammer that Josh Owen was at the moment using.

And now, without glancing back at the stern, the ex-foreman half-turned his head, so as to give a profile view of his face.

Hal, kneeling, turned up quickly to nod the signal that the camera was ready.

Pop! Flare!

As the cap exploded, a blinding flash filled that side of the shed for a brief instant. It was as through a lightning bolt had plunged into the place.

Wholly unprepared for any such happening, Josh Owen let out a yell of fear, rose up and leaped back so that he upset and extinguished his dark lantern.

"Wha-wha-what was that?" he faltered.

In the intense darkness that followed the flash Jack and Hal stole away.