"Begging your pardon, sir," replied Mr. Rivers, not the least ruffled by the rather sharp manner in which the question was asked, "a man can do no more than his best, and I have done that. Then he must be guided by circumstances. Keeping a watch upon a man in London is one thing; keeping watch upon him in a village like this is another. There is no place in the world in which a man can lose himself so easily, if he is inclined that way, as London. I tell you, it's a difficult job to carry out properly, to keep your eye on a man in a large city, with its windings and turnings and crowds of people pushing this way and that. He gives you the slip when you least expect it, and there's the labor of days and weeks thrown away. It is quite a different matter here. A man comes and a man goes, and he can't keep his coming and going from the few people there are about. There are no cabs and omnibuses, no crowds to worry you and put you off the scent. When he moves from one spot to another he has to make preparations; he has to walk along unfrequented roads where he is in full sight of anyone interested in him. There are other drawbacks which one who knows the ropes has to reckon with. He can't keep watch here as he does in a large city; if he prowls and sneaks about, if he's seen haunting a particular spot for days, if he shadows a particular house and keeps his eye on it continually, he draws notice to himself. People ask what for? It comes to the ears of the man he's observing who, in turn, shadows him, and there's his apple cart upset. Another consideration. Strike a man in a street in London, and a crowd collects. Strike a man on the head here when he's prowling up and down a lonely road, and no one sees it. Down he goes like a stone, and he can be done to death, and his body hidden in a hundred holes--and who's the wiser? That couldn't well be done, I grant you, to man, woman, or child who lives here; the absence is remarked, and the relations don't rest till they've found out what has become of the missing one. It's different with a stranger, who stops a day or so, or a week or so, and then, without a word, disappears. So long as he's here the hotel keeper takes an interest in him, because of the bill; the moment he's gone he's forgotten, and it's make way for the next. I've been employed on some difficult jobs in my time, and I'm not sure that this is not going to beat the record." "What makes you think so?" inquired Ronald.