"Sumo is as rash as he is brave," remarked Mori, as he rode along at his friend's side. "If he don't watch out, Patrick will nab him."

While trotting across a rocky shelf, Nattie chanced to look up toward the cone of the nearby volcano. To his surprise, he saw that the vapory mist had given way to a dense volume of pitch-black smoke. Little tongues of flame shot athwart the column at intervals, and hovering over the summit was a cloud of ashes glinting dully in the sun.

"That looks threatening," he exclaimed, calling Mori's attention to it.

"By Jove, Bandai-San is in eruption," was the instant reply. "It is the first time in my memory, too." Then he added, gravely: "Nattie, this comes at a bad time." "Why?"

"If there should be a flow of lava—which is highly probable—our stay in this neighborhood will be dangerous."

"Does it ever reach this far?"

"No; but we must pass near the base of the mountain on our way to the caves."

"And the other party?"

"They will be placed in peril also."