All signals he insisted on attending to himself personally, transmitting them instantly by his bell to the engineer below.

The whole power of the steam engine had been brought to bear on the windlass; the chains could withstand an enormous strain.

The wheels had been carefully oiled and tested beforehand; the signalling apparatus had been subjected to the rigidest examination; and every portion of the machinery had been proved to be in admirable working order.
The chances of immediate and unforeseen danger, it is true, had been somewhat diminished by all these precautions.

The risk, nevertheless, was fearful.

The slightest accident or even carelessness might easily lead to the most disastrous consequence.
Five minutes after two o'clock, the manhole being closed, the lamps lit, and everything pronounced all right, the signal for the descent was given, and the Nautilus immediately disappeared beneath the waters.