I hesitated no further and hurried down the stairs. At the door I was stopped by my host, who inquired whither I was hastening. 'I have just seen a friend,' I answered, and the next moment was in the street. As I pressed forwards I had two minds about keeping my appointment with Pantin in the square behind St. Martin's, but as I went on I reflected that I had to pass that way, and as I might need the notary's aid I would wait there a few minutes, and if he did not come, go straight to de Belin with my news. Although I was not in a frame of mind to observe what was going on around me, I soon became conscious that one of those sudden fogs which extend over the city at this period of the year had arisen, as it were, out of nothing, and in the course of a few minutes I was compelled to slacken pace and pick my way slowly, and with the greatest caution in regard to landmarks, for I could not risk losing my way again. The fog was not a thick one, but it was sufficient, united with the coming evening, to almost blur out the streets and houses and make the figures of passers-by loom out like large and indistinct shadows. Carefully as I had tried to impress the way on my memory, I hesitated more than once as to the route I should take, and it was with something that was like a sigh of relief that I found myself at last behind St. Martin's, whose spire towered above me, a tall, grey phantom. Here I halted for a moment to see if one of the few shadows that flickered now and then through the haze might give some signal by which I might recognise Pantin. It was in vain, and, determining to wait no longer, I set off at a round pace, when I was suddenly arrested by hearing the rich tones of a voice singing: Frere Jacques, dormez-vous? Dormez-vous, dormez-vous? The clear notes rang out through the fog, bringing with them a hundred recollections of the time when I had last heard the chorus. And the voice? That was not to be mistaken. It was de Belin, or else his ghost. Without a moment's hesitation I sang back the lines, advancing at the same time in the direction in which I had heard the voice. I had not gone fifty paces when I saw two tall shadows approaching me, and at the same time heard the verse again. 'Lisois!' I called out. 'It is he,' I heard de Belin say. Then the shadows stopped for a moment, and another and slighter figure joined them. Finally, one came forwards, and, when within a yard or so of me, spoke: 'D'Auriac, is it you?' 'Yes. I was hastening to you. Man, I have discovered all!' '_Morbleu!_' exclaimed the Compte; 'the _chanson_ was a happy thought, else we had missed you in this fog.' 'Is Pantin here? We have not a moment to lose.' 'He is. It was he who guided us here. I have brought a friend with me. Do not ask his name; but speak freely before him, and tell us exactly what you have discovered.'