“Very well,” answered Kearns, “follow me into the grounds. I carefully examined the trees there—not merely the trunks, but also the tops. And among the leaves and branches of some of the tops I discovered something more.”
“Yes.”
“That a number—quite a large number—of the leaves had great blotches where they had been eaten away and a number of the twigs and boughs had big brown splashes. I followed these marks in a westerly direction until I came to the river. There I lost them and all efforts failed to discover where they resumed on the bank. Now, do you begin to discover anything?”
“Speak out,” cried the Professor in ill-restrained excitement; “say what you mean!”
“I’ll endeavor to make it plain to your intelligence, O man of self-convicted density!” retorted Kearns triumphantly. “What do you think was the something which could come, in dead of night, under the window, forty-five feet above the ground, and be unseen by the sentinels above and below; the something which put a mark upon the stone ledge as if it had been moored there by the sharp prongs of a boat-hook; the something that leaves behind it burns and dark brown stains upon the leaves and branches of the trees?”
“What—what—can be the meaning of this?” stammered the Professor, his face working with excitement.
“That there are,” rejoined Kearns, “other distinguished scientists and inventors besides Professor Dean—that the work he dropped fifty years ago has been taken up by others and secretly perfected.”
“An air-ship—an air-ship!” gasped the Professor.
“Yes,” retorted Kearns, “yes, O man of cranks and cog-wheels, an air-ship. An air-ship coming on dark and windless nights, between moons, passing unseen the sentinels on turret and in grounds, and mooring under the windows of the King to deliver its attack. So will it come again! And it is with an air-ship, designed and built by you, that we must and can alone meet the attack.”