"Well, there you ask a question which I can't answer off-hand. What am I going to do with you, eh? That still depends upon a good many things."
As he spoke Juve tossed his hat aside and, looking at a rather high kind of little table, proceeded to remove from it a grey cloth which protected it from dust, and drew it into the middle of the room. This article was composed of a metal body screwed on to a strong tripod, with a lower tray that moved backwards and forwards, and two lateral buttresses with a steel cross-piece firmly bolted on to them above. Upon this framework were two dynamometers worked by an ingenious piece of mechanism. Juve looked at Charles Rambert and explained.
"This is Dr. Bertillon's effraction dynamometer. I am going to make use of it to find out at once whether you are or are not deserving of some little interest. I don't want to tell you more just at present." Juve slipped into a specially prepared notch a thin strip of wood, which he had selected with particular care from one of the heaps of material arranged along the wall. From a chest he took a tool which Charles Rambert, who had had some intimate experience of late with the light-fingered community, immediately recognised as a jemmy. "Take hold of that," said Juve, and as Charles took it in his hand he added: "Now put the jemmy into this groove, and press with all your force. If you can move that needle to a point which I know, and which it is difficult but not impossible to reach, you may congratulate yourself on being in luck."
Stimulated by this encouragement from the detective, Charles Rambert exerted all his force upon the lever, only afraid that he might not be strong enough. Juve stopped him very soon.
"That's all right," he said, and substituting a strip of sheet-iron for the strip of wood, he handed another tool to the lad. "Now try again."
A few seconds later Juve took a magnifying lens, and closely examined both the strip of metal and the strip of wood. He gave a little satisfied click with his tongue, and seemed to be very pleased.
"Charles Rambert," he remarked, "I think we are going to do a very good morning's work. Dr. Bertillon's new apparatus is an uncommonly useful invention."