Now, at the moment when the fellow was turning to the right, into the Avenue de la Grande-Armée, the inspector caught him exchanging signals with a boy of twelve or thirteen, who was walking along the houses on the left-hand side. Twenty yards farther, the man stooped and turned up the bottom of his trousers legs. A bit of orange-peel marked the place. At the same moment, the boy stopped and, with a piece of chalk, drew a white cross, surrounded by a circle, on the wall of the house next to him.
The two continued on their way. A minute later, a fresh halt. The strange individual picked up a pin and dropped a piece of orange-peel; and the boy at once made a second cross on the wall and again drew a white circle round it.
"By Jove!" thought the chief-inspector, with a grunt of satisfaction. "This is rather promising.... What on earth can those two merchants be plotting?"
The two "merchants" went down the Avenue Friedland and the Rue du Faubourg-Saint-Honoré, but nothing occurred that was worthy of special mention. The double performance was repeated at almost regular intervals and, so to speak, mechanically. Nevertheless, it was obvious, on the one hand, that the man with the orange-peel did not do his part of the business until after he had picked out with a glance the house that was to be marked and, on the other hand, that the boy did not mark that particular house until after he had observed his companion's signal. It was certain, therefore, that there was an agreement between the two; and the proceedings presented no small interest in the chief-inspector's eyes.
At the Place Beauveau the man hesitated. Then, apparently making up his mind, he twice turned up and twice turned down the bottom of his trousers legs. Hereupon, the boy sat down on the kerb, opposite the sentry who was mounting guard outside the Ministry of the Interior, and marked the flagstone with two little crosses contained within two circles. The same ceremony was gone through a little further on, when they reached the Elysée. Only, on the pavement where the President's sentry was marching up and down, there were three signs instead of two.
"Hang it all!" muttered Ganimard, pale with excitement and thinking, in spite of himself, of his inveterate enemy, Lupin, whose name came to his mind whenever a mysterious circumstance presented itself. "Hang it all, what does it mean?"
He was nearly collaring and questioning the two "merchants." But he was too clever to commit so gross a blunder. The man with the orange-peel had now lit a cigarette; and the boy, also placing a cigarette-end between his lips, had gone up to him, apparently with the object of asking for a light.
They exchanged a few words. Quick as thought, the boy handed his companion an object which looked—at least, so the inspector believed—like a revolver. They both bent over this object; and the man, standing with his face to the wall, put his hand six times in his pocket and made a movement as though he were loading a weapon.
As soon as this was done, they walked briskly to the Rue de Surène; and the inspector, who followed them as closely as he was able to do without attracting their attention, saw them enter the gateway of an old house of which all the shutters were closed, with the exception of those on the third or top floor.
He hurried in after them. At the end of the carriage-entrance he saw a large courtyard, with a house-painter's sign at the back and a staircase on the left.