"don't let nellie run out of doors, mary margaret, and be careful of the fire, mary margaret. i expect we'll be back pretty soon after dark, so don't be lonesome, mary margaret."

mary margaret laughed and switched her long, thick braid of black hair from one shoulder to the other.

"no fear of my being lonesome, mother campbell. i'll be just as careful as can be and there are so many things to be done that i'll be as busy and happy as a bee all day long. nellie and i will have just the nicest kind of a time. i won't get lonesome, but if i should feel just tempted to, i'll think, father is on his way home. he will soon be here.' and that would drive the lonesomeness away before it dared to show its face. don't you worry, mother campbell."

mother campbell smiled. she knew she could trust mary margaret—careful, steady, prudent little mary margaret. little! ah, that was just the trouble. careful and steady and prudent as mary margaret might be, she was only twelve years old, after all, and there would not be another soul besides her and nellie on the little dipper that whole day. mrs. campbell felt that she hardly dared to go away under such circumstances. and yet she must dare it. oscar bryan had sailed over from the mainland the evening before with word that her sister nan—her only sister, who lived in cartonville—was ill and about to undergo a serious operation. she must go to see her, and uncle martin was waiting with his boat to take her over to the mainland to catch the morning train for cartonville.

if five-year-old nellie had been quite well mrs. campbell would have taken both her and mary margaret and locked up the house. but nellie had a very bad cold and was quite unfit to go sailing across the harbour on a raw, chilly november day. so there was nothing to do but leave mary margaret in charge, and mary margaret was quite pleased at the prospect.

"you know, mother campbell, i'm not afraid of anything except tramps. and no tramps ever come to the dippers. you see what an advantage it is to live on an island! there, uncle martin is waving. run along, little mother."

mary margaret watched the boat out of sight from the window and then betook herself to the doing of her tasks, singing blithely all the while. it was rather nice to be left in sole charge like this—it made you feel so important and grown-up. she would do everything very nicely and mother would see when she came back what a good housekeeper her daughter was.

mary margaret and nellie and mrs. campbell had been living on the little dipper ever since the preceding april. before that they had always lived in their own cosy home at the harbour head. but in april captain campbell had sailed in the two sisters for a long voyage and, before he went, mrs. campbell's brother, martin clowe, had come to them with a proposition. he ran a lobster cannery on the little dipper, and he wanted his sister to go and keep house for him while her husband was away. after some discussion it was so arranged, and mrs. campbell and her two girls moved to the little dipper. it was not a lonesome place then, for the lobstermen and their families lived on it, and boats were constantly sailing to and fro between it and the mainland. mary margaret enjoyed her summer greatly; she bathed and sailed and roamed over the rocks, and on fine days her uncle george, who kept the lighthouse on the big dipper, and lived there all alone, often came over and took her across to the big dipper. mary margaret thought the lighthouse was a wonderful place. uncle george taught her how to light the lamps and manage the light.

when the lobster season dosed, the men took up codfishing and carried this on till october, when they all moved back to the mainland. but uncle martin was building a house for himself at harbour head and did not wish to move until the ice formed over the bay because it would then be so much easier to transport his goods and chattels; so the campbells stayed with him until the captain should return.

mary margaret found plenty to do that day and wasn't a bit lonesome. but when evening came she didn't feel quite so cheerful. nellie had fallen asleep, and there wasn't another living creature except the cat on the little dipper. besides, it looked like a storm. the harbour was glassy calm, but the sky was very black and dour in the northeast—like snow, thought weather-wise mary margaret. she hoped her mother would get home before it began, and she wished the lighthouse star would gleam out on the big dipper. it would seem like the bright eye of a steady old friend. mary margaret always watched for it every night; just as soon as the sun went down the big lighthouse star would flash goldenly out in the northeastern sky.

"i'll sit down by the window and watch for it," said mary margaret to herself. "then, when it is lighted, i'll get up a nice warm supper for mother and uncle martin."

mary margaret sat down by the kitchen window to watch. minute after minute passed, but no light flashed out on the big dipper. what was the matter? mary margaret began to feel uneasy. it was too cloudy to tell just when the sun had set, but she was sure it must be down, for it was quite dark in the house. she lighted a lamp, got the almanac, and hunted out the exact time of sunsetting. the sun had been down fifteen minutes!

and there was no light on the big dipper!

mary margaret felt alarmed and anxious. what was wrong at the big dipper? was uncle george away? or had something happened to him? mary margaret was sure he had never forgotten!

fifteen minutes longer did mary margaret watch restlessly at the window. then she concluded that something was desperately wrong somewhere. it was half an hour after sunset and the big dipper light, the most important one along the whole coast, was not lighted. what would she do? what could she do?

the answer came swift and dear into mary margaret's steady, sensible little mind. she must go to the big dipper and light the lamps!

but could she? difficulties came crowding thick and fast into her thoughts. it was going to snow; the soft broad flakes were falling already. could she row the two miles to the big dipper in the darkness and the snow? if she could, dare she leave nellie all alone in the house? oh, she couldn't! somebody at the harbour head would surely notice that the big dipper light was unlighted and would go over to investigate the cause. but suppose they shouldn't? if the snow came thicker they might never notice the absence of the light. and suppose there was a ship away out there, as there nearly always was, with the dangerous rocks and shoals of the outer harbour to pass, with precious lives on board and no guiding beacon on the big dipper.

mary margaret hesitated no longer. she must go.

bravely, briskly and thoughtfully she made her preparations. first, the fire was banked and the draughts dosed; then she wrote a little note for her mother and laid it on the table. finally she wakened nellie.

"nellie," said mary margaret, speaking very kindly and determinedly, "there is no light on the big dipper and i've got to row over and see about it. i'll be back as quickly as i can, and mother and uncle martin will soon be here. you won't be afraid to stay alone, will you, dearie? you mustn't be afraid, because i have to go. and, nellie, i'm going to tie you in your chair; it's necessary, because i can't lock the door, so you mustn't cry; nothing will hurt you, and i want you to be a brave little girl and help sister all you can."

nellie, too sleepy and dazed to understand very clearly what mary margaret was about, submitted to be wrapped up in quilts and bound securely in her chair. then mary margaret tied the chair fast to the wall so that nellie couldn't upset it. that's safe, she thought. nellie can't run out now or fall on the stove or set herself afire.

mary margaret put on her jacket, hood and mittens, and took uncle martin's lantern. as she went out and closed the door, a little wail from nellie sounded on her ear. for a moment she hesitated, then the blackness of the big dipper confirmed her resolution. she must go. nellie was really quite safe and comfortable. it would not hurt her to cry a little, and it might hurt somebody a great deal if the big dipper light failed. setting her lips firmly, mary margaret ran down to the shore.

like all the harbour girls, mary margaret could row a boat from the time she was nine years old. nevertheless, her heart almost failed her as she got into the little dory and rowed out. the snow was getting thick. could she pull across those black two miles between the dippers before it got so much thicker that she would lose her way? well, she must risk it. she had set the light in the kitchen window; she must keep it fair behind her and then she would land on the lighthouse beach. with a murmured prayer for help and guidance she pulled staunchly away.

it was a long, hard row for the little twelve-year-old arms. fortunately there was no wind. but thicker and thicker came the snow; finally the kitchen light was hidden in it. for a moment mary margaret's heart sank in despair; the next it gave a joyful bound, for, turning, she saw the dark tower of the lighthouse directly behind her. by the aid of her lantern she rowed to the landing, sprang out and made her boat fast. a minute later she was in the lighthouse kitchen.

the door leading to the tower stairs was open and at the foot of the stairs lay uncle george, limp and white.

"oh, uncle george," gasped mary margaret, "what is the matter? what has happened?"

"mary margaret! thank god! i was just praying to him to send somebody to 'tend the light. who's with you?"

"nobody.... i got frightened because there was no light and i rowed over. mother and uncle martin are away."

"you don't mean to say you rowed yourself over here alone in the dark and snow! well, you are the pluckiest little girl about this harbour! it's a mercy i've showed you how to manage the light. run up and start it at once. don't mind about me. i tumbled down those pesky stairs like the awkward old fool i am and i've broke my leg and hurt my back so bad i can't crawl an inch. i've been lying here for three mortal hours and they've seemed like three years. hurry with the light, mary margaret."

mary margaret hurried. soon the big dipper light was once more gleaming cheerfully athwart the stormy harbour. then she ran back to her uncle. there was not much she could do for him beyond covering him warmly with quilts, placing a pillow under his head, and brewing him a hot drink of tea.

"i left a note for mother telling her where i'd gone, uncle george, so i'm sure uncle martin will come right over as soon as they get home."

"he'll have to hurry. it's blowing up now ... hear it ... and snowing thick. if your mother and martin haven't left the harbour head before this, they won't leave it tonight. but, anyhow, the light is lit. i don't mind my getting smashed up compared to that. i thought i'd go crazy lying here picturing to myself a vessel out on the reefs."

that night was a very long and anxious one. the storm grew rapidly worse, and snow and wind howled around the lighthouse. uncle george soon grew feverish and delirious, and mary margaret, between her anxiety for him and her dismal thoughts of poor nellie tied in her chair over at the little dipper, and the dark possibility of her mother and uncle martin being out in the storm, felt almost distracted. but the morning came at last, as mornings blessedly will, be the nights never so long and anxious, and it dawned fine and clear over a white world. mary margaret ran to the shore and gazed eagerly across at the little dipper. no smoke was visible from uncle martin's house!

she could not leave uncle george, who was raving wildly, and yet it was necessary to obtain assistance somehow. suddenly she remembered the distress signal. she must hoist it. how fortunate that uncle george had once shown her how!

ten minutes later there was a commotion over at harbour head where the signal was promptly observed, and very soon—although it seemed long enough to mary margaret—a boat came sailing over to the big dipper. when the men landed they were met by a very white-faced little girl who gasped out a rather disjointed story of a light that hadn't been lighted and an uncle with a broken leg and a sister tied in her chair, and would they please see to uncle george at once, for she must go straight over to the other dipper?

one of the men rowed her over, but before they were halfway there another boat went sailing across the harbour, and mary margaret saw a woman and two men land from it and hurry up to the house.

that is mother and uncle martin, but who can the other man be? wondered mary margaret.

when she reached the cottage her mother and uncle martin were reading her note, and nellie, just untied from the chair where she had been found fast asleep, was in the arms of a great, big, brown, bewhiskered man. mary margaret just gave one look at the man. then she flew across the room with a cry of delight.

"father!"

for ten minutes not one intelligible word was said, what with laughing and crying and kissing. mary margaret was the first to recover herself and say briskly, "now, do explain, somebody. tell me how it all happened."

"martin and i got back to harbour head too late last night to cross over," said her mother. "it would have been madness to try to cross in the storm, although i was nearly wild thinking of you two children. it's well i didn't know the whole truth or i'd have been simply frantic. we stayed at the head all night, and first thing this morning came your father."

"we came in last night," said captain campbell, "and it was pitch dark, not a light to be seen and beginning to snow. we didn't know where we were and i was terribly worried, when all at once the big dipper light i'd been looking for so vainly flashed out, and everything was all right in a moment. but, mary margaret, if that light hadn't appeared, we'd never have got in past the reefs. you've saved your father's ship and all the lives in her, my brave little girl."

"oh!" mary margaret drew a long breath and her eyes were starry with tears of happiness. "oh, i'm so thankful i went over. and i had to tie nellie in her chair, mother, there was no other way. uncle george broke his leg and is very sick this morning, and there's no breakfast ready for anyone and the fire black out ... but that doesn't matter when father is safe ... and oh, i'm so tired!"

and then mary margaret sat down just for a moment, intending to get right up and help her mother light the fire, laid her head on her father's shoulder, and fell sound asleep before she ever suspected it.