Hewitt's client produced a screw-driver from a drawer, and in a very few moments the interior of the little padlock lay uncovered. Hewitt examined the lock attentively for some few minutes, trying the key several times against the levers. Then he stood up and said-- "Mr. Bell, you have made a mistake. This is not your lock at all!" "Not my lock!" exclaimed the broker. "What do you mean? I tell you it is the lock of that box, and I broke it open myself!" "Yes," answered Hewitt calmly, "it was on that box, and you broke it open yourself; but all the same it is not your lock. Let me explain. These are very good little padlocks, with an excellent lever action, 'dogged against detent,' as the technical phrase goes; so that only the key properly made for each lock will open it. They are so good, indeed, as locks, that it would be a waste of time to try picking them, when, because of their small size, it is so very easy to break them apart, just as you have done yourself, and just as I could probably have done in half the time, having had rather more experience. Now that is what has been done with _your_ lock by the person who has your bonds. But of course a broken lock has one disadvantage as compared with a skilfully picked lock--it shows at the first glance what has happened. In this case, Mr. Bell, _your_ lock has been broken and taken away, and the thief, having first provided himself with another padlock of precisely the same make and size, has substituted _that_, locked it with its proper key and so left it!" "What! Then that was why----" "That, of course, was why you supposed it to be out of order when you attempted to open it with _your_ key. As a matter of fact, it is even now in perfectly good order, except for the damage we have jointly committed with the screw-driver. And now, observe! That lock was shut by another key; if the man that did that is as sharp as I suppose he is, he will have got rid of that key at once. But perhaps he hasn't; and if not, then the man who has that key is the thief. At any rate, the key is the clue we must hunt for. Let us have your clerks in one by one, and look at their keys. Some are out at lunch by this time, probably?" "No--I said they might be wanted, so kept them. I thought you might prefer to see them before they went out."