It was not offensively said; but the conviction it expressed was absolute.  Sweetwater recognised the tone, as one of truth, and inwardly laid down his arms.  He could never like the man; there was too much iron in his fibre; but he had to acknowledge that as a foe he was invulnerable and therefore admirable to one who had the good sense to appreciate him.

“I do not want to believe you.”  Thus did Brotherson supplement his former sentence.  “For if I were to attribute those letters to her, I should have to acknowledge that they were written to another man than myself.  And this would be anything but agreeable to me.  Now I am going to my room and to my work.  You may spend the rest of the evening or the whole night, if you will, listening at that hole.  As heretofore, the labour will be all yours, and the indifference mine.”

With a satirical play of feature which could hardly be called a smile, he nodded and left the room.

XXI

A CHANGE

“It’s all up.  I’m beaten on my own ground.”  Thus confessed Sweetwater, in great dejection, to himself.  “But I’m going to take advantage of the permission he’s just given me and continue the listening act.  Just because he told me to and just because he thinks I won’t.  I’m sure it’s no worse than to spend hours of restless tossing in bed, trying to sleep.”

But our young detective did neither.

As he was putting his supper dishes away, a messenger boy knocked at his door and handed him a note.  It was from Mr. Gryce and ran thus: 

“Steal off, if you can, and as soon as you can, and meet me in Twenty-ninth Street.  A discovery has been made which alters the whole situation.”

XXII

O. B. AGAIN

“What’s happened?  Something very important.  I ought to hope so after this confounded failure.”

“Failure?  Didn’t he read the letters?”

“Yes, he read them.  Had to, but—­”

“Didn’t weaken?  Eh?”

“No, he didn’t weaken.  You can’t get water out of a millstone.  You may squeeze and squeeze; but it’s your fingers which suffer, not it.  He thinks we manufactured those letters ourselves on purpose draw him.”

“Humph!  I knew we had a reputation for finesse, but I didn’t know that it ran that high.”

“He denies everything.  Said she would never have written such letters to him; even goes so far to declare that if she did write them—­(he must be strangely ignorant of her handwriting) they were meant for some other man than himself.  All rot, but—­” A hitch of the shoulder conveyed Sweetwater’s disgust.  His uniform good nature was strangely disturbed.

But Mr. Gryce’s was not.  The faint smile with which he smoothed with an easy, circling movement, the already polished top of his ever present cane conveyed a secret complacency which called up a flash of discomfiture to his greatly irritated companion.