roused by the angry uproar of the dogs, a tall, round-shouldered individual appeared in the doorway. he had a melancholy cast of face which was intensified by the lank black hair which hung upon his shoulders. indeed, the man looked more like some street preacher than a suspect with a record of crime behind him. but the eyes were shrewd enough, and so was the smile with which perks greeted venables when the latter disclosed his identity.

"ah, well, you was always one for your little games, sir," he said. "take care of that dog for you? of course i will. and a rare beauty he is. is there anything else, gentlemen?"

"no," venables explained. "mind the dog is for sale if anybody asks questions. you have had him for some time, and you want a big price for him. maybe we shall be able to find a job for you after dark tonight, but as to that i can say nothing for the present. at any rate, there is a five-pound note for you so long as you are discreet and silent. i suppose i can come into your house and write a letter? i'll get you to post it presently."

perks intimated that his house was at the disposal of the visitors, and they all trooped inside. the place looked cosy and comfortable enough, though it was somewhat untidy. at one end of the table was a china bowl, which was filled with odds and ends of small gold and silver ornaments. venables winked at perks, and the latter grinned sheepishly. he snatched up the bowl, and hastily removed it to a side table. ravenspur held out a detaining hand.

"one moment," he said, "i am rather fond of those kind of things. i don't wish to be inquisitive, or to ask idle questions, but unless i am greatly mistaken you have a commonwealth porringer amongst those things. i should like to look at it."

perks bowed to the inevitable. he cursed himself slightly under his breath for his folly in not removing everything, but he felt safe in the hands of his visitors. they would not be likely to ask any questions as to whence the plunder came. by the time that venables had written and stamped his letter, lord ravenspur came forward with a small metal disc in his hand.

"this is a bit of a curio in its way," he said. "intrinsically it is worth very little, only a few shillings at the outside. if you like to take a sovereign for it----"

perks fell in with the suggestion eagerly enough. there was no reason to stay any longer, and the trio set out for the hotel, feeling now that it was possible to move without the slightest fear of alarming the inhabitants of the cottage on the common.

"i suppose that was stolen property we caught perks looking over?" ravenspur asked.

"not the slightest doubt of it," venables said coolly. "i daresay if we had been voted suspicious the signal would have been flashed back to the house to hide it at once. but if you thought it was stolen property, lord ravenspur, why did you invest in that little disc which you took such a fancy to?"

"i am going to tell you something startling," ravenspur replied. "walter, you recollect that little ornament which i bought in rome, and subsequently gave to poor delahay who took a great fancy to it? i had his initials engraved on the back. he wore it on his watch-chain."

"i recollect it perfectly well," walter said. "delahay was wearing it the last time i ever saw him. but what has all this got to do with your purchase of this morning?"

"only that it happens to be the same thing," ravenspur said quietly. "i recognised it in a moment. oh, there is no mistake. here is the disc for you to examine for yourself. you will see the initials and the date on the back of it. as soon as we get time, we must ascertain from inspector dallas if delahay's watch was missing when his body was found. if so, then this opens quite a new phase of the mystery. on the whole, i am not at all sorry that we came here to-day. of course, i kept my knowledge to myself, because i didn't want to arouse perks' suspicions. but if we can contrive to find out from whom he bought this thing we shall be going a long way to clear up the mystery of poor delahay's death."

the matter was discussed at some length over the breakfast, to which all of them did ample justice. once this was finished, they made their way back to the common again, and sat down on the grass to mature their plan of campaign.

"now what we want to do," venables began, "is this. we want to be in a position to make a close study of yonder house without arousing the suspicions of the people there. i racked my brain for a long time before i could think of a feasible scheme. and then it came to to me like an inspiration. what could we do better than pass ourselves off as an ordnance survey party down here on business? that is why i procured the official looking caps, to say nothing of the theodolite and the notebooks. now you, lord ravenspur, have only got to look wise and give us directions. you look exactly like the head of an exploring party. we will pretend to work the theodolite, and make measurements, and all that kind of thing."

"inside the grounds?" walter asked.

"of course," venables went on; "that is the beauty of the scheme. no spot of ground is sacred to an ordnance party. i have actually seen them work inside a church. all we have got to do is to go about our business boldly and be quite firm if anybody attempts to molest us. it may be news to you that nobody can be prosecuted for trespass unless specific damage is done."

the instruments were recovered presently from the hiding-place, and with the theodolite on his shoulder venables stepped boldly on to the lawn in front of the house, and gravely went to work. the blinds were all up by this time. the windows were opened, and a glimpse of well-furnished rooms could be seen in the background. a couple of maids stood in one of the windows, and watched the strangers curiously.

"it looks respectable enough," venables muttered, pretending to be exceedingly busy. "you may depend upon it, this is a tougher job than we anticipated. these servants are all right. you may be sure that they know nothing of what is going on. however, to make certain, i'll ask them for myself."

venables approached the window and asked civilly for the loan of a small piece of string. he came back presently, after a chat of a minute or two, and once more appeared to be wholly engrossed in his instrument. at the same time, he was telling his companions the information which he had gleaned.

"i knew i was right," he said. "the house has been let furnished to an italian gentleman called something or another, i didn't quite catch what, and the people only came down yesterday. those servants go with the freehold, so to speak, and they have all been in their present situation for some considerable time. their master is a city stockbroker, who, with his family, is on the continent for the next month or two. if we are lucky we shall probably get a sight of the italian presently, though i expect we have all got a pretty shrewd notion who the gentleman is."

the work proceeded gravely for a quarter of an hour. levels appeared to be taken, and there was much entering of figures in the notebooks. presently, as walter glanced around him, he drew a deep breath, for there was no mistaking the identity of the slim figure that emerged from one of the open french windows and came striding eagerly down the lawn.

"silva," walter said under his breath. "don't pretend to see him till he gets quite close. i think it would be a good thing if we left all the interviewing to venables."

the italian approached the group and superciliously demanded to know what they were doing there. he looked quite the master of the place in his cool, flannel suit. he had a cigarette between his strong, white teeth.

"why are you trespassing here?" he demanded. "don't you know that this is private property? go, or i will call in the police and give you into custody."

"the police won't help you in this case," venables said with the air of a military man who is quite sure of his ground. "we are here on government business. i don't know if you understand what i mean, but we are surveying, and nobody has a right to interfere with us, providing we do no damage. we can come into the house if we like. indeed, i am not quite sure that we shan't have to. i see you have got a flat roof, sir, with railings round. if we have occasion to take the theodolite up there i will ring the bell and let you know."

the whole thing was so coolly and naturally done that silva was taken aback for the moment. evidently he had come out of the house full of suspicion, and with the fixed intention of getting rid of these intruders as soon as possible. there was an uneasy look in his eyes as venables suggested the roof of the house as the field of action. he deemed it wise to shift his ground altogether.

"that will be very inconvenient," he said, in quite another voice. "i hope you will be able to manage without that if you can. however, if you will give me an hour's notice, i daresay----"

but walter was no longer listening. he was standing up regarding the house with a professional eye. his gaze vaguely took in a dormer window immediately under the roof. there were bars to the window, pointing to the fact that at some time or another the room had been used as a nursery. the window was blank for a moment, then a face appeared and looked out.

that instant was enough for walter. there was no mistaking those features. they were those of vera rayne.