it was late in the afternoon before prout hit upon the trail he was looking for. he had been keeping the telegraph and the telephone busy. the scent was still hot, and it was just possible that he might come upon some trace of the missing notes before they left the country.

at any rate, it could only have been hours since they found their way into the hands of the murdered man. according to his letter, he had received ￡400 in gold--probably the result of some blackmailing transaction--after which he had hastened to turn them into banknotes for transmission, probably abroad.

now there is only one place of business where a man can turn so large a sum of money into notes, and that place must be a bank. there are a great many banks in london, and the difficulty in finding the right one was enhanced by the fact that nobody besides prout knew that there was anything wrong about these particular notes. on the face of it, the transaction was a very casual one.

it was nearly four o'clock before prout raised the trail. on the previous day but one a cashier at the national credit bank had changed ￡400 in gold into notes for a stranger who answered to the description of the murdered man. prout dashed down to leadenhall street in a fast hansom. the cashier was a little nervous, but quite willing to speak freely.

"i remember the transaction perfectly well," he said. "we do a lot of money-changing and that kind of thing, as our foreign connection is a large one. i should not have heeded the matter but for noticing the curious disfigurement of the man's hands."

"covered all over with orange blotches, eh?" asked prout.

"quite so. the man was all twisted from his hip, and he had a crooked nose."

"you needn't say any more," prout said crisply. "that's the man. you changed the gold for the victim of the corner house tragedy. got the numbers?"

the numbers were forthcoming, of course--190753 to 190832, the first half of which eighty ￡5 notes had been alluded to in the murdered man's letter.

"so far so good," prout remarked. "it's not a very pleasant experience, but i am sorry i have not finished yet. i shall have to trouble you to come as far as raven street with me and identify the body."

it was well over at length, but the mild little cashier had nothing to say except that he really must go over to the raven's arms and have a little brandy. abstemious man as he was, he felt it was necessary. presently the blood came back to his face again, and his dilated pupils contracted.

"that's the man, sergeant," he said. "and i hope i have seen the last of him. are you going to advertise those notes?"

prout replied for the present he had no intention of doing anything of the kind. the thief knew nothing about the letter, or he assuredly would have destroyed it. he would imagine that he had got off scot free with his booty, and thus might walk into the trap prepared for him.

"we shall lie low for the present," prout said. "and i will ask you to do the same. you may mention this matter to your manager, but not to another soul. i'll try and get down before five and see your manager myself."

it was not a bad day's work, and it spurred on prout to fresh endeavours. he carefully examined the fireplace, he tested the windows, but nothing rewarded his endeavours beyond a blacklead-brush thrown into the corner of the scullery together with a cake of blacklead recently opened.

"now where does this come in?" he asked himself. "there isn't a grate in the house that has been touched for years. and this cake is not quite dry yet. and a bit of yellow soap in the tray over the sink that would be as hard as a chip if it had been here since the people left. but it hasn't. murderer may have washed his hands, which is exceedingly likely, but what did he want blacklead for?"

prout looked keenly around him. he opened the back door into a yard that gave on to a lane at the back of the house. the bricks were damp and mossy, and on them was something that looked like the print of wheels. the door leading to the lane was wide, and on the edge on both sides something patchy glistened. prout touched it with his fingers.

"now what does it mean?" he asked himself. "what game were they playing?"

the black edging of the gate-posts was fresh blacklead.

the little discovery gave a new twist to prout's thoughts as he drove down to the national credit bank. he had no particular object save to see the manager and impress upon him that in the interests of justice the whole thing must be kept a profound secret. there was no difficulty about that: the cashier was indignant, for he had already given his promise on the matter.

"not that you will ever see those notes again, sir," prout said. "by this time they are probably on their way to the continent, whence they may begin to dribble back one by one in the course of months. still, one never can tell."

the manager was sympathetic; at the same time he looked at the clock, which was drawing very near to closing time. there was a lull outside in the traffic. prout took up his hat and prepared to depart.

but the same moment his friend, the cashier, came rushing in. his eyes were gleaming behind his spectacles.

"a most extraordinary thing, sir," he stammered. "those notes that sergeant prout came about just now are----"

"get on," the manager said impatiently, "get on."

"have been paid in to the credit of a customer, or part of them."

"numbers?" prout snapped. "which part of them?"

"190753 to 190792," the cashier replied.

"every note," prout cried, "every blessed note mentioned in the dead's man's letter."