In the course of his investigations he himself had found cause to suspect the existence of several such explosives, though he had lacked time and opportunity to prosecute his studies in that direction.

However, he indicated the field which should be explored, and the best way of proceeding.

In his opinion it was there that lay the future.

And in a broad and eloquent peroration, he declared that explosives had hitherto been degraded by being employed in idiotic schemes of vengeance and destruction; whereas it was in them possibly that lay the liberating force which science was seeking, the lever which would change the face of the world, when they should have been so domesticated and subdued as to be only the obedient servants of man.
Throughout this familiar discourse Pierre could feel that Francois was growing impassioned, quivering at thought of the vast horizon which the master opened up.

He himself had become extremely interested, for he could not do otherwise than notice certain allusions, and connect what he heard with what he had guessed of Guillaume's anxiety regarding that secret which he feared to see at the mercy of an investigating magistrate.