The air steadily darkened, and suddenly the dim horizon in the far southwest was cut by a vivid flash of lightning.

Low thunder grumbled over the distant hills.
"It's a storm, an' it's to be a whopper," said Shif'less Sol.
"Ay," returned Ross, who had been back among the horses, "an' it may save us.

All you fellows be sure to keep your powder dry." There would be little danger of that fatal catastrophe, the wetting of the powder, as it was carried in polished horns, stopped securely, nor would there be any danger either of the salt being melted, as it was inclosed in bags made of deerskin, which would shed water.
"One of the men," continued Ross, "has found a big gully running down the back end of the hill, an' I think if we're keerful we can lead the horses to the valley that way.

But just now, we'll wait." Henry and Paul were watching, as if fascinated.

They had seen before the great storms that sometimes sweep the Mississippi Valley, but the one preparing now seemed to be charged with a deadly power, far surpassing anything in their experience.