“He is engaged,” answered one of the draughtsmen; “very particularly engaged.  I am afraid you won’t be able to see him this afternoon.  Can I give him any message?”

“This is two—­the second time I have come to-day.  Not two hours ago Mr. Dixon himself tells me to call again.  I have a very important—­very excellent steam-packing to show him that is very cheap and the best of the market.”  The man tapped his bag.  “I have just taken orders from the largest railway companies.  Can not I see him, for one second only?  I will not detain him.”

“Really, I’m sure you can’t this afternoon; he isn’t seeing anybody.  But if you’ll leave your name——­”

“My name is Hunter; but what the good of that?  He ask me to call a little later, and I come, and now he is engaged.  It is a very great pity.”  And the man snatched up his bag and walking-stick, and stalked off, indignantly.

Hewitt stood still, gazing through the small aperture in the doorway.

“You’d scarcely expect a man with such a name as Hunter to talk with that accent, would you?” he observed, musingly.  “It isn’t a French accent, nor a German; but it seems foreign.  You don’t happen to know him, I suppose?”

“No, I don’t.  He called here about half-past twelve, just while we were in the middle of our search and I was frantic over the loss of the drawings.  I was in the outer office myself, and told him to call later.  I have lots of such agents here, anxious to sell all sorts of engineering appliances.  But what will you do now?  Shall you see my men?”

“I think,” said Hewitt, rising—­“I think I’ll get you to question them yourself.”

“Myself?”

“Yes, I have a reason.  Will you trust me with the ‘key’ of the private room opposite?  I will go over there for a little, while you talk to your men in this room.  Bring them in here and shut the door; I can look after the office from across the corridor, you know.  Ask them each to detail his exact movements about the office this morning, and get them to recall each visitor who has been here from the beginning of the week.  I’ll let you know the reason of this later.  Come across to me in a few minutes.”

Hewitt took the key and passed through the outer office into the corridor.

Ten minutes later Mr. Dixon, having questioned his draughtsmen, followed him.  He found Hewitt standing before the table in the private room, on which lay several drawings on tracing-paper.

“See here, Mr. Dixon,” said Hewitt, “I think these are the drawings you are anxious about?”

The engineer sprang toward them with a cry of delight.  “Why, yes, yes,” he exclaimed, turning them over, “every one of them!  But where—­how—­they must have been in the place after all, then?  What a fool I have been!”

Hewitt shook his head.  “I’m afraid you’re not quite so lucky as you think, Mr. Dixon,” he said.  “These drawings have most certainly been out of the house for a little while.  Never mind how—­we’ll talk of that after.  There is no time to lose.  Tell me—­how long would it take a good draughtsman to copy them?”