"explain yourself, you young rascal," exclaimed my uncle, gripping me by the shoulder in his excitement.

in reply i handed over my solution, explaining in a few words the principle of the magic square. for a few moments neither of them spoke. the pater, seizing a ruler, made a rough pencil mark on a chart of the pacific that lay on the table; then, bringing his powerful fist down so heavily that the glasses and drawing instruments fairly jumped, he almost shouted—

"why, you are a regular brick, reggie! that's it right enough."

"are there any islands shown on the chart?" asked my uncle herbert.

"several; but let's turn up findlay's directory of the pacific. hello! what have we here? 'truk or hogoleu islands. this group is composed of four or five lofty basaltic islands, surrounded by a barrier reef.... discovered by captain duperrey, june 24, 1824' (that is, if humphrey trevena hadn't done so a century before). 'the northernmost of the group is in lat. 7° 42' 30" n.' (probably san philipo island skipped the navigator's memory). it seems possible that an island does exist at this position eh, herbert?"

"certainly. do they give any further information?"

"yes; here is a choice piece: 'captain cheyne, of the brigs "naiad" and "will-o'-the wisp," came here to collect bêche-de-mer, and were completely taken off their guard by the apparent friendliness of the natives, who at first assisted them to build their curing-houses. as soon as the "naiad" left, they attacked the "wisp" with a force of 2,000 men, and were only repulsed with desperate fighting and the loss of six killed and five wounded. they also seized the long-boat, which was recovered the same day.... they had a great number of large spanish knives, and were armed with brass-hilted cutlasses.'"

"'spanish knives and brass-hilted cutlasses,'" repeated my uncle. "that's strange."

"it certainly points to a wreck of some spanish war-vessel in bygone days."

"what do you intend to do in the matter?"

"why, fit out an expedition," replied my father decisively. "i've already formed a rough plan of action, but it is too late to discuss it to-night. it's time we were all turned in and fast asleep."

so saying, my father swept the papers and charts off the table, locked the former in a safe, and placed the metal box with the now solved cipher in his pocket, then motioned us to retire, and extinguished the lamp.

but for me, sleep was an impossibility. the exciting events of the past few days, culminating in my fortunate discovery, kept me awake, and in almost a fever of suppressed mental activity i was continually turning from side to side in a fruitless endeavour to sleep.

outside the wind was howling across the harbour, making the trees shiver and creak in a weird and disturbing manner. presently the clock struck two, and at almost the same time a current of air rushed into my room, causing the half-open door to swing back against the wall.

"surely they cannot have forgotten to shut the hall door," i thought, and, jumping out of bed, i walked silently towards the staircase. the other inmates had been more fortunate than i; my father was sleeping soundly, while his brother was snoring heavily, the place seemingly trembling under the vibrations of his sonorous efforts, and even as i listened i heard a faint click as if the dining-room door was being opened.

instantly i crept into uncle's room, gently closed the door, and shook him by the shoulder.

"wake up!" i whispered. "there's some one broken into the house."

"no luck," he muttered. "twenty fathoms down. try again to-morrow," and, turning over, he recommenced his discordant snoring. "wake up!" i repeated, redoubling the shaking performance. "there's a burglar after the cipher."

the word "cipher" did it, for in an instant he was up and fully awake.

"hush! listen!" and carefully opening the door, i hastened to my father's room to arouse him.

we sallied forth to meet the foe; my father and uncle led the way, the latter grasping a revolver, while i followed, feeling somewhat disjointed in my lower limbs.

at the top of the stairs we waited for further signs of the burglar, and in the dismal silence, broken only by the moaning of the wind, i could feel my heart throbbing violently against my ribs. at length came the unmistakable sounds of some one moving cautiously.

a man must naturally feel at a disadvantage when, clad mainly in pyjamas, he is forced single-handed to tackle a house-breaking ruffian; but, with three of us, and the comforting reassurance imparted by the revolver, the deficiency of wardrobe counted for little.

suddenly the silence was broken by the noise of a furious scuffle, followed by a shriek of pain, and, concealment being no longer necessary, the brothers dashed downstairs. my uncle led in the race, but, tripping over a man's body, he lay half-stunned, while my father, who followed more cautiously, narrowly escaped the same fate. then some one rushed quickly through the hall and began to fumble with the lock of the front door, and, as the door was thrown violently open, there was a blinding flash from the vicinity of the floor, followed by another yell of pain, and the pungent smell of gunpowder filled the air.

"that's settled his hash, howard," i heard my uncle exclaim. "get a light and see what we are up to."

i made for the dining-room to light the lamp, and as i crossed the hall my bare feet stepped in a pool of warm liquid. with trembling fingers i struck a match and lighted the lamp, and, returned to the scene of the struggle.

my uncle was leaning against the wall, the still smoking revolver in his hand, and my father was leaning over a motionless figure huddled at the foot of the stairs, while a stream of blood, through which i had stepped, slowly welled across the floor.

"the man has been stabbed!" exclaimed uncle herbert. "whatever does it mean?"

"get another light—a hurricane lamp, there's one in the kitchen—and run the other man down. you winged him right enough, herbert; he can't be far away."

the light was procured, and following a well-defined trail outside the door, we ran the other burglar to earth, in a shrubbery close to the garden gate.

simultaneously, my uncle and i recognised him—it was the brazilian seaman who had tried to stab my uncle on the wreck, and whom i had seen lying on the cliff path.

while my uncle covered him with a revolver, for he snarled viciously like a wounded animal at bay, my father relieved him of his knife, and, lifting him by their combined efforts, they carried him into the house; but before reaching the door he had fainted.

"he's shot through the fleshy part of his right leg," said my father. "just put on a temporary bandage till we can attend to the other beauty. whatever made them fight each other like that, i wonder?"

"i don't know," replied my uncle, ripping the man's trousers with a penknife and winding a long strip of linen round the wound, for the bullet had cut a clean hole right through the brazilian's leg. "but you see there is something very mysterious in the manner in which this scoundrel has followed me up."

"now for the other man," exclaimed my father. "i am afraid he has been badly hurt. why, herbert, you have had a gash yourself—look!"

"pooh! a mere nothing. i hardly felt it."

"but it's bleeding pretty freely."

"yes, the brazilian made a jab at me as he broke away. but who's this?"

they had lifted the man who had been left lying at the foot of the stairs, and carried him, still unconscious, into the kitchen. he was apparently quite a young man, with closely cropped hair and clean-shaven face, or, rather, his chin was covered with a four days' growth of bristling hair, while his dress consisted of a close-fitting suit of dark blue cloth, the coat-tails tucked in under the trouser band. "here's a fine bird!" remarked uncle herbert, as he began to cut away the odd-looking clothing to get at a wound in the man's side. "you know where he comes from?"

"no," replied my father.

"bodmin. he's escaped from the naval prison."

"i wonder what he's been up to," remarked my father thoughtfully. "a naval prisoner does not usually associate with foreign seamen, and burglars to boot."

"it's a clean cut, and not particularly dangerous," announced uncle herbert. "bring the light closer, reggie. hello!" he added, looking at my face, which must have been horribly white. "this won't do. run away to the other room, and, keep your head between your knees till you feel better. i can't have three patients on my hands."

i did as i was bid, for everything was beginning to whirl round. presently my father came in to get some brandy, for the second patient was recovering. as daylight began to dawn, they carried the man upstairs to my room, and presently, after a good deal of talking, my father and uncle came downstairs.

"run upstairs and get your things on, reggie," said my father. "i want you to fetch the police sergeant. but, remember, don't say a word to any one about the man we have upstairs. it's only the brazilian we are going to give in charge; he's coming to now. remember what i say, and i'll tell you the reason later."

"did i understand him to say that the brazilian was coming downstairs?" i heard my father remark.

"yes, i believe so," replied my uncle.

"then he must have been in one of our rooms. only to think that that dirty scoundrel was hanging around us with his knife while we were asleep! i'll go upstairs and see if anything is touched."

a moment later i heard my father shout, "it's gone!"

"what's gone?" asked uncle herbert.

"the box containing the cipher."

"it can't be far, at all events," said my uncle. "let's search the brute."

i am afraid they were none too gentle with the man, but a thorough search revealed nothing.

"try the place where we caught him," suggested the pater, and we all three went outdoors, carefully examining the well-defined trail. after a lengthy search we found, not only the box, but a bundle of papers cunningly hidden under the shrubbery in a tangled mass of twigs and leaves.

after glancing at the contents of the metal box, which was still intact, my father opened the packet of papers, and, to our surprise, they were the actual documents filched from my uncle's cabin on the ill-fated "andrea doria."

"you have only forestalled fate by a few hours, reggie," remarked the pater. "you see, here is the exact key to the cipher—the figures your uncle took to be merely business papers. however, run on down for the police."

as i passed through the hall to get my cap, i gave an involuntary exclamation of surprise, for there were no signs of the brazilian.

in reply to my shout, my father and uncle came running up, and their astonishment was, in spite of the situation, comical to behold. we made a hasty yet thorough search of the house and grounds, with no result. the man had vanished as completely as if he had been provided with wings.

"but he cannot get far, with a badly wounded leg," i remarked.

"it certainly is strange; but he must have a wonderful nerve to play 'possum like that. however, i think we need not send for the police, after all; for they will think we are either mad or else inventing fairy-tales."

everything considered, there was not much to grumble about. we had, it is true, a wounded man on our hands, and uncle herbert had received a slight cut from the brazilian's knife; but as a set-off we had regained the papers, though they served merely to confirm my solution to the cipher, while the brazilian, who had an ounce of lead through his leg, would hardly care to repeat his burgling exploits after such a disastrous ending to his first attempt.

while at breakfast they told me about the wounded man upstairs, and why i was not to have mentioned him to the police.

the man, who gave his name as alec johnston, a scotsman, had broken out of bodmin naval prison, where he had been sent after being sentenced by court-martial for the heinous offence, in naval law, of striking a superior officer. he appeared, said my father, to be a well-set-up, healthy young fellow, with a fair amount of intellect, and there was no reason to doubt his story.

left an orphan at an early age, he was sent by his relatives to the training-ship "st. vincent." in due course he was "passed out" and sent on a sea-going ship, and, by thorough devotion to his duty, bade fair speedily to become a petty officer. by some means or other he incurred the enmity of a bully, who, by a fawning subservience to his superiors, had been recently made a bos'n's mate, and the climax was reached when johnston refused to participate in a drunken spree ashore. from that time his life on board became intolerable. under the cloak of discipline the bos'n's mate seized every possible opportunity to humiliate and insult the young seaman, till one day the young scot turned upon his tormentor and struck him violently in the face.

the circumstances of this breach of discipline were reported to the commander, and at the court-martial, where the evidence in support of the prosecution was given by a ship's corporal and two seamen, neither of whom witnessed the assault, the draconic sentence of two years' hard labour, to be followed by dismissal from h.m. service, was passed upon the hapless scot.

smarting under the gross injustice of his sentence, johnston seized the first opportunity of effecting his escape under circumstances of remarkable audacity, and, travelling by night and hiding by day, he made his way towards the coast, trusting to find a sympathetic fisherman to give him a passage away from the danger zone.

chance led him to the neighbourhood of polruan, and, as a change of clothes was essential, he resolved to break into a house and procure some garments less distinctive than his own. a fortunate circumstance prompted him to effect an entry into our house.

now, as it happened, the brazilian had removed a pane of glass and opened a window barely ten minutes before, and, in order to facilitate his retreat, he had drawn the bolts of both the front and back doors. this he had done without disturbing any of us, and had actually crept into my father's room and removed the cipher from his coat-pocket.

in the meantime the sailor had found the front door ajar and had cautiously made his way into the house, though the slight noise he had made caused me to be on the alert. in the hall he took down an overcoat and hat, but, requiring other articles of clothing, he made up his mind to risk a visit to the upstairs rooms.

just as he was ascending the stairs he encountered the brazilian, and, in the darkness, each imagined the other to be one of the occupiers of the house. in almost dead silence they grappled, struggling fiercely and determinedly, till, overbalancing, they both fell in a heap at the foot of the stairs, at the very moment that we were leaning over the balustrades.

then it was that the brazilian, whipping out his formidable knife, stabbed the sailor and broke away, only to be "winged" by my uncle's shot.

thus we were under an obligation to the unfortunate alec johnston for his burglarious act. but for him the brazilian might have got clean away with both the cipher and its key. as far as we knew, he might be an agent for some syndicate of rogues in pernambuco, who, knowing the history of the "san philipo," might instantly fit out a vessel to attempt to recover the treasure.

both my father and his brother expressed themselves very strongly on the subject of the gross injustice done to the young seaman, and, coming to the conclusion that there would be no moral wrong done in concealing the man under these circumstances, they decided to befriend him, or at least to take no active steps in preventing his bid for freedom.