“Let me see if I understand it,” persisted Kearns with obstinacy. “This liquid residuum, as you call it, leaks away through the bottom of the air-ship, doesn’t it?” “You may put it that way,” said the Professor, smiling. “And that blamed old dripping liquid residuum would either burn into, or else make a deep brown stain upon any fairly soft material it touched, wouldn’t it?” “Yes, yes,” exclaimed the Professor excitedly; “a dark brown stain. But how--how did you know this?” “Not bad, eh?” retorted Kearns, “for a marvel of density! In course of time--O sage of a century of Wisdom!--and under your able direction, you’ll find that almost human intelligence of mine gradually developing itself.” “But how did you know this?” persisted the Professor. “Patience! O Aged Wise Man of the decomposing chemicals, main turrets and cylindrical tubes,” retorted Kearns; “patience, I say! Didn’t I tell you that under my methods everything must come in its proper order? Listen, then, and you’ll learn.” “I’m all attention,” said the Professor. “I commenced my operations this morning,” began Kearns, “by making a thorough examination of the _locus_. I’ll not weary you with a long description of the preliminary details of my investigation--how I extracted and took possession of the bullet which had been fired and thoroughly examined the apartment, its surroundings--everything.” “I think we may trust you for that,” remarked the Professor, with a smile. “The King’s sleeping apartment,” continued Kearns, “is in the extreme western wing of the palace. It is a spacious apartment, with two alcoves. One of these alcoves contains the royal couch; the other, the royal bath. There are four windows and two doors. One of these doors--that leading out on the passage--is securely sealed from the inside; the other leads into the antechamber. In this antechamber there is on duty every night a Captain of the Guard, and the outer corridor is watched by three sentinels. At the extreme end of the corridor is another apartment also at the disposal of the Captain of the Guard. Should anyone appear at the end of the corridor, the sentinel would signal to his comrade, who would in turn signal to the third sentinel and the officer on duty would come forth and receive the visitor in the apartment at the extreme end of the corridor. This is done to prevent any sound in the antechamber disturbing the King.” “Quite elaborate precautions, I see,” commented the Professor. “Just so,” resumed Kearns. “Now, last night, Captain Bingham, of the Guard, was on duty and I’m satisfied from what he tells me that no one visited the corridor after the King had retired. In fact, nothing happened until the sharp ring of the electric signal in the King’s chamber caused Captain Bingham to rush in and we know what he found there.” “Yes, yes,” assented the Professor.