Acting on this very plain hint, I retired to the clerks’ office, where I found Mrs. Hornby and Juliet, the former undisguisedly tearful and terrified, and the latter calm, though pale and agitated.

“We had better start at once,” I said, when we had exchanged greetings.  “Shall we take a cab, or walk?”

“I think we will walk, if you don’t mind,” said Juliet.  “Mrs. Hornby wants to have a few words with you before we go into court.  You see, she is one of the witnesses, and she is terrified lest she should say something damaging to Reuben.”

“By whom was the subpoena served?” I asked.

“Mr. Lawley sent it,” replied Mrs. Hornby, “and I went to see him about it the very next day, but he wouldn’t tell me anything—­he didn’t seem to know what I was wanted for, and he wasn’t at all nice—­not at all.”

“I expect your evidence will relate to the ‘Thumbograph,’” I said.  “There is really nothing else in connection with the case that you have any knowledge of.”

“That is just what Walter said,” exclaimed Mrs. Hornby.  “I went to his rooms to talk the matter over with him.  He is very upset about the whole affair, and I am afraid he thinks very badly of poor Reuben’s prospects.  I only trust he may be wrong!  Oh dear!  What a dreadful thing it is, to be sure!” Here the poor lady halted to mop her eyes elaborately, to the surprise and manifest scorn of a passing errand boy.

“He was very thoughtful and sympathetic—­Walter, I mean, you know,” pursued Mrs. Hornby, “and most helpful.  He asked me all I knew about that horrid little book, and took down my answers in writing.  Then he wrote out the questions I was likely to be asked, with my answers, so that I could read them over and get them well into my head.  Wasn’t it good of him!  And I made him print them with his machine so that I could read them without my glasses, and he did it beautifully.  I have the paper in my pocket now.”

“I didn’t know Mr. Walter went in for printing,” I said.  “Has he a regular printing press?”

“It isn’t a printing press exactly,” replied Mrs. Hornby; “it is a small thing with a lot of round keys that you press down—­Dickensblerfer, I think it is called—­ridiculous name, isn’t it?  Walter bought it from one of his literary friends about a week ago; but he is getting quite clever with it already, though he does make a few mistakes still, as you can see.”  She halted again, and began to search for the opening of a pocket which was hidden away in some occult recess of her clothing, all unconscious of the effect that her explanation had produced on me.  For, instantly, as she spoke, there flashed into my mind one of the points that Thorndyke had given me for the identification of the mysterious X.  “He has probably purchased, quite recently, a second-hand Blickensderfer, fitted with a literary typewheel.”  The coincidence was striking and even startling, though a moment’s reflection convinced me that it was nothing more than a coincidence; for there must be hundreds of second-hand “Blicks” on the market, and, as to Walter Hornby, he certainly could have no quarrel with Thorndyke, but would rather be interested in his preservation on Reuben’s account.