she hardly felt the prick, not sufficiently in any case to make her utter a scream.  And, mind you, the scoundrel had every facility, through his friendship with Mr. Errington, of procuring what poison he required, not to mention his friend’s visiting card.  We cannot gauge how many months ago he began to try and copy Frank Errington in his style of dress, the cut of his moustache, his general appearance, making the change probably so gradual, that no one in his own entourage would notice it.  He selected for his model a man his own height and build, with the same coloured hair.”

“But there was the terrible risk of being identified by his fellow-traveller in the Underground,” suggested Polly.

“Yes, there certainly was that risk; he chose to take it, and he was wise.  He reckoned that several days would in any case elapse before that person, who, by the way, was a business man absorbed in his newspaper, would actually see him again.  The great secret of successful crime is to study human nature,” added the man in the corner, as he began looking for his hat and coat.  “Edward Hazeldene knew it well.”

“But the ring?”

“He may have bought that when he was on his honeymoon,” he suggested with a grim chuckle; “the tragedy was not planned in a week, it may have taken years to mature.  But you will own that there goes a frightful scoundrel unhung.  I have left you his photograph as he was a year ago, and as he is now.  You will see he has shaved his beard again, but also his moustache.  I fancy he is a friend now of Mr. Andrew Campbell.”

He left Miss Polly Burton wondering, not knowing what to believe.

And that is why she missed her appointment with Mr. Richard Frobisher (of the London Mail) to go and see Maud Allan dance at the Palace Theatre that afternoon.

CHAPTER XII

THE LIVERPOOL MYSTERY

“A title—­a foreign title, I mean—­is always very useful for purposes of swindles and frauds,” remarked the man in the corner to Polly one day.  “The cleverest robberies of modern times were perpetrated lately in Vienna by a man who dubbed himself Lord Seymour; whilst over here the same class of thief calls himself Count Something ending in ‘o,’ or Prince the other, ending in ‘off.’”

“Fortunately for our hotel and lodging-house keepers over here,” she replied, “they are beginning to be more alive to the ways of foreign swindlers, and look upon all titled gentry who speak broken English as possible swindlers or thieves.”

“The result sometimes being exceedingly unpleasant to the real grands seigneurs who honour this country at times with their visits,” replied the man in the corner.  “Now, take the case of Prince Semionicz, a man whose sixteen quarterings are duly recorded in Gotha, who carried enough luggage with him to pay for the use of every room in an hotel for at least a week, whose gold cigarette case with diamond and turquoise ornament was actually stolen without his taking the slightest trouble to try and recover it; that same man was undoubtedly looked upon with suspicion by the manager of the Liverpool North-Western Hotel from the moment that his secretary—­a dapper, somewhat vulgar little Frenchman—­bespoke on behalf of his employer, with himself and a valet, the best suite of rooms the hotel contained.