“Those wholly ignorant of meteorological phenomena might so pronounce, perhaps, but never one who has given the matter either thought or study,” promptly responded the professor, in no wise loth to give a free lecture, no matter how brief it might be, perforce. “It is merely nature seeking to restore a disturbed equilibrium; a current of colder air, in search of a temporary vacuum, caused by—”

“But isn't that just what produces cy—tornadoes, though?” interrupted Waldo, with scant politeness.

“Precisely, my dear boy,” blandly agreed their mentor, rubbing his hands briskly, while peering through rain-dampened glasses, after that departing storm. “And I have scarcely a doubt but that a tornado of no ordinary magnitude will be the final outcome of this remarkable display. For, as the record will amply prove, the most destructive windstorms are invariably heralded by a fall of hail, heavy in proportion to the—”

“Then I'd rather be excused, thank you, sir!” again interrupted the younger of the brothers, shrugging his shoulders as he stepped forth from shelter to win a fairer view of the space stretching away towards the south and the west. “I always laughed at tales of hailstones large as hen's eggs, but now I know better. If I was a hen, and had to match such a pattern as these, I'd petition the legislature to change my name to that of ostrich,—I just would, now!”

Bruno proved to be a little more amenable to the law of politeness, and to him Professor Featherwit confined his sapient remarks for the time being, giving no slight amount of valuable information anent these strange phenomena of nature in travail.

He spoke of the different varieties of land-storms, showing how a tornado varied from a hurricane or a gale, then again brought to the front the vital difference between a cyclone, as such, and the miscalled “twister,” which has wrought such dire destruction throughout a large portion of our own land during more recent years.

While that little lecture would make interesting reading for those who take an interest in such matters, it need scarcely be reproduced in this connection, more particularly as, just when the professor was getting fairly warmed up to his work, an interruption came in the shape of a sharp, eager shout from the lips of Waldo Gillespie.

“Look—look yonder! What a funny looking cloud that is!”

A small clump of trees growing upon a rising bit of ground interfered with the view of his brother and uncle, for Waldo was pointing almost due southeast; yet his excitement was so pronounced that both the professor and Bruno hastened in that direction, stopping short as they caught a fair sight of the object indicated.

A mighty mass of wildly disturbed clouds, black and green and white and yellow all blending together and constantly shifting positions, out of which was suddenly formed a still more ominous shape.