somehow, or the other the news of my uncle's adventures were noised abroad far beyond the limits of our village, and for a week or more we were besieged with letters and telegrams from various people, most of them absolute strangers, offering congratulations, but more frequently asking impertinent questions about the "san philipo" treasure. several london and county papers sent representatives down to interview the survivor of the wreck; but to all requests my uncle turned a deaf ear, politely yet firmly refusing to give any information, so that interest in the mystery grew rather than waned; and exaggerated rumours, amusing no doubt to others, appeared in various journals, greatly to my father's and uncle's disgust.

in accordance with his resolution, my father went over to pridmouth and obtained the metal box with its precious contents, together with the clothes my uncle was wearing at the time of the shipwreck. curiously enough, his watch, which had been in the water for nearly an hour, was practically uninjured, only a faint trace of rust showing near the hinge, while, on being rewound, it ticked as merrily as ever.

we had arranged to defer the opening of the box till the afternoon, when all three of us would be present; but i firmly believe my father could not resist the temptation of glancing inside to make sure the parchment was still there.

he arrived home in high good humour, for on the return journey, he had picked up a horseshoe and had crossed the ferry in company with a hunchback, both of which incidents are regarded, even in these matter-of-fact days, as being conducive to a run of "good luck"; and preparations were immediately made for the examination of the mysterious relic of old humphrey trevena's seafaring days.

i handled the box with a feeling almost of reverence. it was about the size of a cigar-case, and made of a dull, heavy metal resembling bronze, although tarnished with the effects of time and exposure to the salt water. it was embellished on the front of the outside by quaint figures representing boreal urging a seventeenth-century frigate on its course, with neptune and britannia holding a friendly conference in the background, and, on the back, by a monogram of letters "h.t." and the date 1719.

"open it, reggie," said my father; and, after i had fumbled about with the spring for a few moments, the lid flew open, and i saw for the first time the puzzling piece of parchment which was fated to lead us through great perils by land and by water ere we accomplished our quest.

with trembling hands i unfolded the paper, my father and uncle looking eagerly over my shoulder. as uncle herbert had already informed us, there was nothing but a big square subdivided into a host of smaller ones, and a few unintelligible words and the symbols of degrees, minutes, and seconds of latitude and longitude, with no figures given, save a solitary figure 1.

here, in fact, is a copy of it—

"well?" asked my uncle, elevating his eyebrows. "what do you make of it, howard?"

"give me time. what does he mean by 'steer nor.'-east,' i wonder?"

"that's what has been puzzling me, for in his log humphrey states definitely that he followed the 'san philipo' in a nor'-westerly direction, consequently the directions appear to be misleading."

"possibly they were intended to be so," replied my father dryly. "but these marks of latitude and longitude—do they convey anything?"

"nothing, except that certain numbers are evidently intended to fill in the squares so indicated, and the puzzle is, what are these numbers?"

"ah, what?"

"i tell you what; i can see it all now. amongst the other papers that were stolen was the key to the cipher. don't you remember my saying that one sheet contained a host of figures? howard, old man, i am a careless idiot and deserve to be kicked for my negligence."

"it can't be helped," replied my father philosophically. "what is done cannot be undone, so the less said about it the better. we must rack our brains to find a solution to the cipher without the aid of the key. don't look so glum, herbert. better luck next time."

long after i had gone to bed my parent and his brother pored over the stubborn cipher, either with the aid of frequent references to the log of the "anne" or the chart of the pacific, which had been ordered from potter's some time ago. they must have sat up half the night, for they were both late at breakfast next morning and were horribly short-tempered in consequence.

i went to school that morning as usual, but the excitement of the previous day proved too much for my attention, and, in consequence, i was sent to detention for an hour. if there is anything i loathe, detention holds an easy first, for the monotony of an hour's imprisonment at the end of the day, is particularly galling to a boy fond of outdoor pursuits. i am sure the junior masters do not appreciate the task of looking after the delinquents either, and newman, the second form master, was no exception. so in less than a quarter of an hour he cleared out, leaving us to our own devices.

the fellow at the desk next to mine, a boarder named ward, of the upper fifth, who was ever in hot water, was busily engaged in covering sheets of paper with roughly drawn lines, and as he appeared to derive a considerable amount of satisfaction from the task, i remarked:

"what are you up to, ward; noughts and crosses?"

"noughts and crosses, my grandmother!"

"what, then?"

"trying my hand at a magic square."

"a magic what?"

"square, you ass! look and see for yourself."

on closer examination i found that he had drawn a rough square and had subdivided it into nine smaller ones, by means of two horizontal and two vertical parallel lines, and the spaces thus formed he was busily filling in with the numbers 1 to 9.

"what happens when you finish it? where does the magic part of the show come in?" i asked. "it seems a very tame sort of amusement."

"not when you get thoroughly interested in it," replied ward. "you see, the idea is to arrange the figures so that each of the horizontal, vertical, and diagonal rows make a total of fifteen. it takes a bit of juggling, i assure you, and i am told that even larger magic squares can be formed. ah! that's done it."

with a slightly growing interest i watched ward manipulate the figures until he arrived at the solution, which, for some unexplained reason, i copied down—

"there are other arrangements of the numbers," he remarked; "for instance, you can get another magic square by exchanging the top and bottom lines or the outside vertical columns; but i have not managed a larger square yet. hello! here comes newman, so it must be close on half-past five."

the miserable hour over, i made my way homewards, revolving in my mind the problem of humphrey trevena's cipher, till by some unaccountable impulse, as i was sitting in the ferry-boat that plies between fowey and polruan, i formed some hazy connection between ward's magic square and the exaggerated chessboard design that was so sorely puzzling my father and uncle.

rapidly the connection grew, till by the time the boat ran alongside polruan quay-steps i firmly assured myself that old humphrey's cipher was based on the principle of a magic square; and, arguing that the solution of the "fifteen" square must be governed by some fixed rule, i determined to try to solve the working of ward's puzzle, and to apply the principle, if possible, to the more complicated cipher.

with this object in view, i began my task. my father and uncle had gone out to the yacht club, so that i knew i should be free from interruption.

my first step was to make a copy of the magic square and indicate the order of the numbers by straight lines from one to the other. when completed, the diagram looked positively bewildering, and the only information i could gather was that the numbers 4, 5, 6 formed one of the diagonals, and ran obliquely from the bottom left-hand corner to the upper right-hand one, and that the centre number was the 5, or, the numeral next to half the highest number of the squares.

next i tried a "twenty-five" square, the diagonal reading 11, 12, 13, 14, 15. the position of the 1 i had already fixed by that in the smaller square, which, by a sudden inspiration, i remembered occupied the same relative position in humphrey trevena's cipher. as in the "nine" square the 7 came immediately below the 6; i adapted the principle by placing the 16 in the square below the 15.

all this took time, but i felt satisfied that i was on the right track, till i came to the rest of the numbers, and, try how i would, i could not apply the principle any farther.

at length, with bewildered brain and aching head, i gave up the task for the time being, and, putting on my cap and calling my dog, i set out for a ramble to try and cool my heated brow.

i intended to walk in the direction of lanteglos, and make a circuit through hall walk, bodinneck ferry, and fowey, but, on reaching the little hamlet of pont, i sat down on the handrail of the little wooden bridge, and amused myself by sending the dog into the water. at length i desisted, and, ignoring the antics of my faithful companion, i fell into a brown study—a thing under ordinary circumstances i rarely do.

twilight was drawing in, and against the vivid red hue in the western sky the placid waters of the tree-fringed creek made an entrancing picture, that harmonized with my dreams of adventure in the future, like a presage of good fortune.

unconsciously i found myself toying with a pocket compass i invariably carried, and as my eyes lingered for a moment on the delicately balanced needle, i saw in my mind's eye, not the compass card, but the outlines of a magic square, with the needle forming the puzzling diagonal. in the haphazard position i held the compass the needle pointed to n.e. on the card, and, like a flash, occurred the directions scrawled upon the mysterious cipher, "steer nor'-east."

"i have it!" i exclaimed aloud in my excitement. "'steer nor.'-east' must be old humphrey's way of expressing the sequence of the numbers on his cipher; and that is the direction of the diagonal."

without a moment's delay, i hastened home to make a fresh onslaught upon the puzzle, and, to make a long story short, i solved the "twenty-five" square by constructing two similar squares on its north and south sides—i.e. the top right-hand sides—and starting with the figure 1 and working in a n.e. direction, so that directly a number fell within one of the divisions of the adjacent squares, i transferred it to the corresponding division of the original design. but when by this means i came to a space already occupied by a number, i found, by consulting the already completed nine-divisioned square, that the next number was placed in the vacant space that invariably occurred below.

the completed square, which i regarded with considerable satisfaction, appeared as under—

total of each vertical, horizontal, and diagonal line = 65.

now came the crucial test of constructing a square with the same number of subdivisions as there were on humphrey's cipher, and an intelligent application of the figures to the symbols of latitude and longitude; but here i was nonplussed, for i had no copy of the cipher, neither could i remember the actual numbers of subdivisions.

just then, however, my father and uncle returned, and while at supper they did not fail to notice my excitement.

"whatever is the matter with you, reggie?" asked uncle herbert. "you look like a cat on hot bricks."

i was burning with impatience to let them know of my evening's work and its results, but, fearing that after all there might be some flaw in my theory, and having another motive in view, i managed to restrain myself.

little more was said during the meal, but on its completion preparations were made to continue the investigations of the mystery.

"i say, pater," i exclaimed. "don't you think it would be better to make a copy of the cipher: it would save the original, you know."

"just so, reggie, i will; but i think it's about time you went to bed."

"another hour won't make much difference," i replied. "you see, to-morrow's a holiday."

my father assented, and gleefully i set about the task of making a duplicate of the cipher, of which i was now firmly convinced i held the key.

it was not a long business, and when completed, i stealthily removed a second copy which i had obtained by means of a carbon paper, and announced my intention of "turning in."

it was, however, far from my thoughts to go to bed, and directly i reached the solitude of my room i set to work to fill up the blank spaces of the cipher, which, thanks to my previous trials with the smaller squares, was a comparatively rapid and easy task.

in less than an hour i had completed the solution, checking the totals, which in every case amounted to the sum of 1,695; and, applying the marks of latitude and longitude, i found that the position was 7° 24' 41" n. and 151° 45' 11" w., which, in spite of the absence of an atlas, i knew would be somewhere in the pacific ocean.

cautiously i made my way downstairs, holding the completed cipher rolled tightly in my hand. the dining-room door was slightly ajar, and through the opening i could see my father and uncle leaning over the table, which was littered with charts, papers, and writing materials.

"i am afraid we are checkmated," i heard my father remark despondently. "the treasure of the 'san philipo,' will never come within our grasp."

as i entered the room they both looked up in amazement.

"reggie!" exclaimed my father deprecatingly.

"all right, pater," i replied, with the boldness acquired by my success. "i want to make a bargain with you."

"a bargain? i don't understand."

"what i mean to say is this: if you make a search for the 'san philipo' treasure, promise me that i can go too."

"bless the boy!" ejaculated uncle herbert. "what does he mean?"

"the possibility of a search is very remote," said my father, "as we have absolutely no definite information to work upon, and no likelihood of gaining any; but i really don't understand what you mean by the word 'bargain.'"

"i mean," i replied stoutly, "that if i find a key to the cipher, do i take part in the search?"

"i see no reason why you shouldn't if——"

"then you promise?"

"yes."

"thanks," i replied, flourishing the paper i held in my hand.