It was with the greatest difficulty that Walter restrained himself. He dared not look round again until Silva\'s back was turned and the Italian returned to the house. Even then it would have been impolitic to make a sign, for there might be prying, suspicious eyes looking from other windows who would understand, and then the whole of Venables\' ingenious scheme would be wasted. Turning sideways, Walter glanced up again. It seemed to him that he could still catch the outline of Vera\'s figure. Then a desperate idea occurred to him. He stooped down and went through all the\' motions of patting and caressing some favourite animal. There was just the outside chance that Vera might take this as an allusion to Bruno, and the knowledge that the dog had put her friends on her track. The girl was sharp and quick enough, and she might easily, in the light of events, guess the identity of the trio on the lawn. Before Walter could speak, Venables glanced in his direction and smiled.

"Well, did you see it?" the former asked.

"Did you see it, too?" Walter exclaimed. "I am glad of that because now I know I was not mistaken."

"See what?" Ravenspur asked, apparently busy with his notebook. "I didn\'t notice anything."

"It was Vera," Walter whispered. "Whatever you do, don\'t look up now. I daresay you happened to notice a dormer window in the roof, with bars in front of it. Well, a moment ago, I saw Vera\'s face there. What a fortunate thing it was that we thought of the dog last night! I knew he would not lead us astray."

"So far, so good," Venables murmured. "And now, don\'t let us forget what we are here for. The next thing is to go to the back of the house and go through the same pantomime there. What I want to do is to find the easiest way of getting into the place, and to ascertain how many people there are in the house, and where they sleep. For that purpose it is necessary to be as near the back door as possible. I shall want you two to keep up the masquerade while I pump the servants. With any luck we shall have got all we want to know by lunch time."

Venables was as good as his word. By two o\'clock the survey was complete, and the trio were trudging off to their hotel to talk the matter over. It was in a little arbour in the garden, over cigars and coffee, that Venables unbosomed himself.

"It is like this," he explained. "I told you before that those servants were quite innocent of anything going wrong in the house, and so it turns out. The tenant is Silva, and his sister, the countess of something or another, whose name doesn\'t matter, though it will be necessary to see the lady later on. There is no basement, and, as far as I could see, there would be very little difficulty in obtaining entrance to the house by means of a small window that gives light and air to the larder. On the ground floor are four living rooms, which we need not trouble about. There are four bedrooms on the first floor, and four on the second, to say nothing of the room in the roof. I didn\'t dare to be too curious about this roof room, but I am told that Silva uses it himself for certain experiments, and that, as his experiments are dangerous, he keeps the key in his pocket. The explanation sounds simple, and quite suffices for the servants; but I think we have got a pretty fair idea of what is going on in that roof room. I have managed to make a rough sort of plan of the bedrooms, so that we shall be fairly safe when we come to break into the house, as we shall have to do, soon after midnight, if you are agreeable."

"Isn\'t that rather a dangerous proceeding?" Walter asked. "I didn\'t know that you added housebreaking to your other accomplishments. Being amateurs, we are certain to make a noise, and you may be pretty sure that Silva only sleeps on one ear."

"Oh, that part will be managed for us all right," Venables said coolly. "The housebreaking item of the programme will be carried out by Perks. The rascal knows he is quite safe in our hands, and he will do all that is necessary for about a ten-pound note. Once his work is accomplished we will send him about his business. The rest we can manage ourselves. It will go hard, indeed, with us if Miss Rayne is not back in our hands again before daylight."

Walter could think of no better scheme to offer, so that Venables was allowed to have his own way. There was nothing for it now but to pass the time as best they could till midnight The hours stole slowly on. The darkness deepened and night came at length. Dinner had been a thing of the past for some time, and it was getting near eleven o\'clock before the trio, accompanied by Perks, made their way in the direction of the common. They lay quietly on the turf there till a distant church clock struck twe............