A spouting of reddened water gave Bob the location, and he put the Grampus about, so as to face the danger and bring the cachalot in front of the port torpedo tube.
“Tell them to make ready in the torpedo room!” shouted Bob. “They must fire the Whitehead the moment I give the word.”
Dick repeated the order. The torpedo was contrived so as to travel at a certain distance under water. If discharged at too great a distance from the whale it would sink to its normal depth, and so miss the charging monster altogether. Bob, watching the cachalot with sharp eyes, awaited the right moment for letting the Whitehead go.
The whale left a bloody track as it hurled itself nearer and nearer.
“Fire!” shouted Bob suddenly.
A gurgling swish, a spluttering cough, and a thud followed. The surface of the sea directly ahead of the submarine was full of ripples that marked the passing of the deadly infernal machine.
“Full speed astern!” cried Bob.
Dick repeated the order to Gaines. Barely was the motion of the propeller reversed when whale and torpedo met. There was a dull roar, and the sea lifted high in a veritable flurry. The Grampus slid backward rapidly, rocking on the troubled waters. Then, the lifted waves having descended, the whale was seen torn cruelly and lying on his back. Already the triangular fins of sharks were in evidence, rushing from every direction upon the prey.
Bob descended to the engine room and found Dick steering with one hand and wiping the perspiration from his face with the other.
“A tight squeak!” Dick muttered. “We’re out one torpedo, but you saved the boat.”