(Letter from Mr. Mitchel to Mr. Barnes)
"My dear Barnes:—
"I read your letter with considerable interest. As you very truly say, the case was intricate because of its simplicity. As you had followed up three theories with apparently the result that you were at least tentatively satisfied that neither held the key to the mystery, it seemed proper to take up the affair where you had left it, and to endeavor to learn whether or not Mrs. Upton had lied to you, and still had the stud in her own possession. For this and other reasons I decided to adopt your suggestion and call upon Mrs. Upton. I did so, and, as you surmised, was cordially received. She met me first in her parlor, and I at once stated to her the object of my visit.
"'Mrs. Upton,' said I, 'you are perhaps aware that I have a friendly regard for Mr. Barnes, the detective, ever since the affair of my little wager. I have received a letter from him this morning in which he states that an important criminal case compels him suddenly to leave the city; he has also given me a succinct statement of the few facts in relation to the loss of your stud, and has asked me to interest myself in the solution of this little mystery.'
"'And you mean to do it?' she exclaimed, impulsively. 'Why, how delightful! Of course you will find out all about it. To think that you, Mr. Mitchel, the man who outwitted Mr. Barnes, will take up my case! I am honored, I assure you.'
"I give you her exact words, though her flattery was somewhat embarrassing. In the course of the conversation she referred to you in terms which I repeat, though I do not at all share her poor estimate of your ability.
"'Of course,' said I, 'I am not a detective, yet I do take a trifling interest in these little problems, I find it mentally exhilarating to measure minds, as it were, with these wrong-doers. Thus far I have generally been successful, which, however, only proves my claim that those who stoop to crime are not really ever sound mentally, and consequently, either from too little or from too much care, some slight detail is overlooked, which, once comprehended by the investigator, leads unerringly to the criminal.'
"'Ah, how delightfully you talk!' said she. 'I am so glad you have taken this up, for, do you know, I rather thought Mr. Barnes a little dull, not to say stupid. Why, he actually suggested that my maid took the stud!'
"Here, I thought, was an opportune moment to follow the method which you employed with Mrs. Beaumont, and by a sudden, unexpected accusation, to endeavor to surprise the truth from her. I said:
"'Oh, Mr. Barnes has given up that idea now, and has almost adopted one even more startling. He thinks that perhaps you took the stud yourself."