The colonists, motionless, anxiously awaited the result of this exploration, when a shout from the engineer made them hasten forward.
They soon joined him, and were at once struck with a disagreeable odor which impregnated the atmosphere.
The odor, easily recognized, was enough for the engineer to guess what the smoke was which at first, not without cause, had startled him.
"This fire," said he, "or rather, this smoke is produced by nature alone.
There is a sulphur spring there, which will cure all our sore throats." "Captain!" cried Pencroft.

"What a pity that I haven't got a cold!" The settlers then directed their steps towards the place from which the smoke escaped.

They there saw a sulphur spring which flowed abundantly between the rocks, and its waters discharged a strong sulphuric acid odor, after having absorbed the oxygen of the air.
Cyrus Harding, dipping in his hand, felt the water oily to the touch.
He tasted it and found it rather sweet.

As to its temperature, that he estimated at ninety-five degrees Fahrenheit.

Herbert having asked on what he based this calculation,-- "Its quite simple, my boy," said he, "for, in plunging my hand into the water, I felt no sensation either of heat or cold.