Especially useful is it in commerce.

I know that, having had some experience of commercial life." At this point in the conversation Nigel was startled by what was to him an absolutely new sensation, namely a shaking or trembling of the whole cavern, accompanied by faint rumbling sounds as if in deeper caverns below him.
He glanced quickly at his host and at the negro, but to his surprise these remarkable men seemed not to be aware of the shaking, although it was severe enough to cause some of the furniture to rattle.

Observing his look of surprise, Moses remarked, with a benignant though capacious smile, "Mountain's got de mulligrumps pritty bad jist now." "We are pretty well accustomed to that," said the host, observing that Nigel turned to him for an explanation.

"No doubt you are aware that this region is celebrated for earthquakes and volcanoes, so much so that the inhabitants pay little attention to them unless they become unusually violent.

This island of Krakatoa is itself the fragment of an extinct volcano; but the term 'extinct' is scarcely applicable to volcanoes, for it is well known that many which were for centuries supposed to be extinct have awakened to sudden and violent activity--'quiescent' might be a more appropriate term." "Yes," said Moses, ceasing to masticate for purposes of speech; "dem 'stinkt volcanoes hab got an okard habit ob unstinkin' dereselves hereabouts when you don' 'spect it of 'em.