It was the look of the insane sailor.
If his companions had still held any lingering doubts about his insanity, it was sufficient to dispel them.

It was the true stare of the maniac.
It was not long continued.

Scarce had they resumed their seats when the man, once more elevating his arms in the air, uttered another startling shriek, if possible louder and wilder than before.

He had stepped upon one of the boat seats, and stood with body bent, half leaning over the gunwale, in the attitude of a diver about to make his headlong plunge.
There could be no mistaking his intention to leap overboard, for his comrades could see that his muscles were strained to the effort.
All three--the captain, Murtagh, and the Malay--suddenly rose again, and leant forward to lay hold on him.

They were too late.