so far as anstruther was concerned, he might have been going about his usual business. he evidently had no fear on the score of interruption, and, indeed, there was little cause, seeing that the bank was so substantially built, and that from top to bottom the windows were protected with iron shutters.

"there is absolutely nothing to be afraid of," he said. "good gracious, man, have you no pluck at all? i declare when i look at you that i could kick you as one does a cowardly cur."

but carrington was impervious to insult. his face was ghastly, and the strong glare of the electric lights showed the beads of moisture upon his forehead.

"it is all very well for you," he growled. "the greater the danger the better you seem to like it."

"there isn't any danger," anstruther protested. "didn't you tell me that the police had no special orders as far as the bank was concerned? and everybody knows you have two night watchmen. besides--oh, i have no patience with you!"

anstruther turned away from the other, and began to fumble with the lock of a small black bag which he carried in his hand. he signified to carrington that the latter should lead the way to the vaults below. carrington produced a bunch of keys from his pocket. anstruther sneered openly.

"oh, that's it," he said. "going to make it all smooth for us, are you? of all the fools i ever came across! why not go outside and tell everybody what we are going to do? those are all patent shove locks, which the most expert thief could never pick, and you are going to tell the police later on that they have been opened with an ordinary key. don't forget that you have got to face the police later on, and endure a cross-examination that will test your nerve to the uttermost. we are going to blow those locks up, and these are dynamite cartridges to do it."

carrington's face was almost comic in its dismay. his ghastly, sweat-bedabbled face fairly quivered. but he made no further protest; he bent before the sway of anstruther's master mind.

"i don't wish to interfere with you," he stammered. "but the infernal noise which is likely to----"

anstruther kicked his companion aside.

"we either do it or we don't do it," he said. "it doesn't matter a rap one way or the other to me. now which is it to be?"

carrington hesitated no longer. he simply submitted himself entirely to the hands of his companion. in a dazed, fascinated kind of way he watched anstruther insinuate a dynamite cartridge of minute proportions into the lock of the door. then anstruther drew carrington back as far as possible, and the tiny fuse began to work. there was just a tiny spurt of blue flame, followed by a muffled shock, and the door fell slowly back.

"there," anstruther cried triumphantly. "what do you think of that? do you suppose that noise was heard outside? now come on; let us serve them all alike."

the sound of their footsteps came to the ears of those watching in the counting house, and at frequent intervals the sullen explosions could be heard. seymour rose to his feet, and whispered to his companions to follow. they crept cautiously along the flagged stairway until they reached the vault in which the two strong rooms were situated. a couple of electric lights gave sufficient illumination for the purpose of the amateur burglars, who were now busily engaged on the locks of the strong room. this was altogether a different business to blowing in the lock of an ordinary door, for the entrance to the strong room was secured with six bolts, all of which would have to be destroyed.

it was possible to find a secure hiding-place in the thick darkness outside the radius of the two electric lights. it was an interesting moment, and even seymour was conscious of a sensation of excitement.

"stand back," anstruther said. "everything is ready. you had better lie down on your face, as i am using six charges now instead of one. if they all go off together the thing will be accomplished to our mutual satisfaction."

the hint was not lost upon the listeners. there was a moment of intense excitement, and then came a dull, heavy roar, that seemed to shake the building almost to its foundations. almost before the reverberations had died away, the huge door of the strong room swayed with a zigzag motion, and came smashing on the floor.

"there," anstruther cried triumphantly. "what do you think of that, my friend? i flatter myself that that is a real workmanlike job. all you have to do now is to keep a stiff upper lip, and give the police all the information they require. anything of value inside?"

"not very much, i am afraid," carrington responded. "a fair amount of old family plate, and perhaps twenty or thirty thousand pounds' worth of securities. i suppose we had better leave all that there; look better, don't you think?"

"leave your head there," anstruther sneered. "now i put it to you, as a man supposed to be possessed of sense--would any thief leave a single item of value behind?"

anstruther asked the question with a contemptuous curl of his lip. he was wiping his hands now on a piece of greasy cotton waste in which the dynamite cartridges had been wrapped to prevent contact.

"this is going to be a unique sort of burglary," he continued. "trot out what you've got in the way of plate, and i'll take my pick of it as a kind of fee in reward for my night's service. if there is one soft place in my heart, it is for antique silver. take your time--we are not in the least likely to be interrupted."

with his coat off and his shirt sleeves turned up, carrington set to work in earnest. once he had plunged headlong into the business, he seemed to have lost all his nervousness and hesitation. one after the other the great wooden cases were turned out and examined by anstruther as eagerly as a schoolboy pores over something new in the way of a bird's nest. presently he held aloft a magnificent specimen of a silver dish. it was perfectly plain: fine old hammered silver, bearing a quaint design around the edge.

"benvenuto cellini for a million," he cried. "dish and ewer, together with a set of the finest posset cups i've ever seen. how much over ten thousand pounds would this fetch at christie's? well, i'm very sorry for the late owner, but exceedingly pleased so far as i am concerned. i'll take this for my fee, carrington."

the two dived into the strong room again, where they appeared to be overhauling other boxes of treasure. the gleams of the electric light fell upon the service of plate which anstruther had so greatly admired. by its side, in strange contrast, laid a piece of cotton waste with which anstruther had wiped his hands a minute or two before. without a word of warning to his companions, seymour darted across the floor of the vault; and, seizing the cotton waste, proceeded to rub it vigorously over the surface of the service of plate which anstruther had marked down for his own.

his conduct was so unexpected and so peculiar, that jack and rigby could only look at one another in astonishment. they did not know in the least what to make of this extraordinary man?uvre on the part of their colleague. but there was evidently much method in his madness; he was not in the least likely to run the risk of detection to gratify an apparently meaningless whim. he was back again an instant later, and jack could hear him chuckling to himself as if he had accomplished something quite out of the common. he seemed to feel that some explanation was necessary.

"i dare say you thought that peculiar," he said; "but you will understand all in good time. i didn't go out of my way to spoil everything for the mere sake of playing amateur housemaid."

apparently the task which anstruther and carrington had set themselves was finished by this time, for they came out of the strong room empty handed. all the same, their figures appeared to be pretty bulky, and doubtless their pockets were well filled with illicit gain.

"but you don't mean to carry that stuff home," carrington protested. "well known as you are, it would be an act of criminal folly to carry that plate through the streets at this time of the morning. as to myself----"

"but have you no private safe of your own?" anstruther asked. "the same remark you made to me just now applies to you. is there anything more to wait for?"

carrington disappeared within the strong room again for a last look round, followed by anstruther. they had no sooner disappeared than seymour was on his feet again, making hurriedly for the stairway leading to the counting house. he had not been gone many seconds before there came stumbling noisily down the stairs the form of one of the night watchmen, rubbing his eyes drowsily, and asking what was going on. it was quite evident to rigby and jack that seymour had deliberately aroused the sleeping man for some subtle purpose of his own. the man cried out again to know what all this meant, and carrington and anstruther came darting from the strong room.

"by heaven! he has come to his senses," anstruther muttered. "i thought that dose was quite strong enough. i am very sorry, but seeing that he has learned so much----"

there was murder in anstruther's eyes, and carrington saw it. still dazed and stupid from the result of the drug, the watchman was gazing about him like a man just emerging from a heavy bout of intoxication. it was evident that he did not recognize his employer, though senses and reason were fast coming back to him. as he staggered towards the strong room door a murderous look crept into anstruther's eyes again, and something bright gleamed in his hand. carrington hastened forward.

"no, no," he cried hoarsely. "i will have none of that, i have gone too far already. i could bear with imprisonment, but the mere thought of a noose round my neck----"

he almost staggered up to the dazed watchman, and shook him violently. the latter seemed to comprehend at length.

"wake up, gregory," carrington stammered. "there has been a burglary here. i had occasion to come down to the bank for something, and found that the premises had been broken into. go for the police."

anstruther studied the watchman's features with broody, malignant eyes. his quick brain was working rapidly. it was quite evident that the watchman had not yet fully grasped the situation. it would be some time before he could find a policeman and give him a fairly coherent account of what had happened.

"not a moment to be lost," he cried. "let us go up-stairs at once to your room and lock all this stuff up in your private safe. no one will think of looking for it there. now don't say you haven't got the key with you."

carrington nodded breathlessly, and immediately anstruther began to pack up the cellini service of plate which had so greatly fascinated him.

"come on at once," he said. "let us get this stuff in hiding, and then we can face the police."

they had only to don their coats again and make their way as soon as possible to carrington's private room. as they passed up the stairs seymour signed to his companions to follow.

they were only just in time, for as they emerged into the alley the watchman was returning with the constable. they squeezed close against the wall, securing the friendly cover of the darkness, and a moment later they were in gresham street.

"what is to be done next?" rigby said.

"i think that is pretty obvious," seymour chuckled. "so far as i can see this is a nice little job for inspector bates."