The lighthouse men were most painstaking in their task of explaining everything to their young guests. The clockwork and manual-worked machinery for actuating the occulting light, the ingenious construction of the lenses of the lantern, the usual and the emergency means of supplying its illumination—all were in turn shown to the Scouts, none of whom had ever been in a lighthouse before.
"Bill!" exclaimed one of the keepers in the midst of a technical discourse. "It's coming on thick. You can't see the Island already. Throw me the key of the rocket store."
The keeper addressed as Bill handed over the required article, and then drew back the curtains of the lantern room, which, during the day, were always kept closed in order to prevent the rays of the sun from damaging the dioptric lenses of the lantern. A sea-fog—another sign of an approaching storm—had banked up with considerable rapidity. Wreaths of vapour were curling over the waters of Seal Bay, while, as the keeper had announced, the Island itself was quite lost to view.
"This'll give you a chance to see how we work the explosive fog-signals," remarked the man, as he hauled down a fishing-rod-like apparatus from outside the lighthouse. "Here are the charges—gun-cotton, fired electrically; two every five minutes."
Securing the two cartridges to the forked ends of the rod, the keeper hoisted the latter to its former position and touched a key. A sharp crack, that in the outer air resembled the discharge of a seven-pounder, announced that the first of the warning signals had been fired. Ten seconds later the second was discharged, and the keeper lowered the holder to recharge it.
"What makes the light blink?" asked Scott.
"This revolving screen, sir," answered the keeper. "It is worked by the action of a slowly falling weight, after the principle of a grandfather's clock. We have to wind it every two hours. If that goes wrong we have to grind the lantern round by hand, and a precious stiff job it is."
"That's where we would come in handy," observed Baker. "Scouts to the rescue, eh?"
"All right, young gentlemen. I'll bear that in mind, and if the apparatus goes wrong while you are on Seal Island we'll signal for a party of you to bear a hand. There'll be stiff arms and aching backs in the morning, I'll warrant."
The inspection came to an end at last, and Mr Trematon led his Scouts out into the now dense fog.