oh, i say, bonnie—bonnie connaught! priscilla! wait a minute," called a girl from across the links, as the two were strolling homeward one afternoon, dragging their caddie-bags behind them. they turned and waited while bonnie's sophomore cousin, mildred connaught, dashed up. she grasped them excitedly, and at the same time glanced over her shoulder with the air of a criminal who is being tracked.

"i want to tell you something," she panted. "come in here where no one will see us"; and she dived into a clump of pine-trees growing by the path.

priscilla and bonnie followed more leisurely, and dropped down on the soft needles with an air of amused tolerance.

"well, mildred, what's the matter?" bonnie inquired mildly.

the sophomore lowered her voice to an impressive whisper, although there was not a person within a hundred yards. "i am being followed," she said solemnly.

"followed!" exclaimed bonnie, in amazement. "are you crazy, child? you act like a boy who's been reading dime novels."

"listen, girls. you mustn't tell a soul, because it's a great secret. we're going to plant the class tree to-night, and i am chairman of the ceremonies. everything is ready—the costumes are finished and the plans all arranged so that the class can get out to the place without being seen. the freshmen haven't a suspicion that it's going to be to-night. but they have found out that i'm chairman of the committee, and, if you please,"—mildred's eyes grew wide with excitement,—"they've been tracking me for a week. they have relays of girls appointed to watch me, and i can't stir without a freshman tagging along behind. when i went down to order the ice-cream, there was one right at my elbow, and i had to pretend that i'd come for soda-water. i have simply had to let the rest of the committee do all of the work, because i was so afraid the freshmen would find out the time. it was funny at first, but i am getting nervous. it's horrible to think that you're being watched all the time. i feel as if i'd committed a murder, and keep looking over my shoulder like—like macbeth."

"it's awful," bonnie shuddered. "i'm thrilled to the bone to think of the peril a member of my family is braving for the sake of her class."

"you needn't laugh," said mildred. "it's a serious matter. if those freshmen come to our tree ceremonies, we'll never hear the last of it. but they are not going to come," she added with a meaning smile. "they have another engagement. we chose to-night because there's a lecture before the archæological society by some alumna person who's been digging up remains in rome. the freshmen have been told to go and hear her on account of their latin. imagine their feelings when they are cooped up in the auditorium, trying to look intelligent about the roman forum, and listening to our yells outside!"

priscilla and bonnie smiled appreciatively. it was not so long, after all, since they themselves were sophomores, and they recalled their own tree ceremonies, when the freshmen had not been cooped up.

"but the trouble is," pursued mildred, "that it's more important for me to get there than any one else, because i have to dig the hole,—peters is really going to dig it, you know; i just take out the first shovelful,—but i can't get there on account of that beastly scout. as soon as she saw me acting suspicious, she'd run and warn the class."

"i see," said bonnie; "but what have priscilla and i to do with it?"

"well," said mildred, tentatively, "you're both pretty big, you know, and you're our sister class, and you ought to help us."

"certainly," acquiesced bonnie; "but in just what way?"

"well, my idea was this. if you would just stroll down by the lake after chapel, and loiter sort of inconspicuously among the trees, you know, i would come that way a little later, and then, when the detective person came along after me, you could just nab her and—"

"chuck her in the lake?" asked bonnie.

"no, of course not. don't use any force. just politely detain her till you hear us yelling—take her for a walk. she'd feel honored."

bonnie laughed. the program struck her as entertaining. "i don't see anything very immoral in delaying a freshman who is going where she has no business to go. what do you say, pris?"

"it's not exactly a sunday-school excursion," acknowledged priscilla, "but i don't see why it isn't as legitimate for us to play detective as for them."

"by all means," said bonnie. "behold sherlock holmes and his friend dr. watson about to solve the mystery of the shadowed sophomore."

"you've saved my life," said mildred, feelingly. "don't forget. right after chapel, by the lake." she peered warily out through the branches. "i've got to get the keys to the gymnasium, so the refreshments can be put in during chapel. do you see anybody lurking about? i guess i can get off without being seen. good-by"; and she sped away like a hunted animal.

bonnie looked after her and laughed. "'youth is a great time, but somewhat fussy,'" she quoted; and the two took their homeward way.

they found patty, who was experiencing a periodical fit of studying, immersed in dictionaries and grammars. it was under protest that she allowed herself to be interrupted long enough to hear the story of their proposed adventure.

"you babies!" she exclaimed. "haven't you grown up yet? don't you think it's a little undignified for seniors—one might almost say alumnæ—to be kidnapping freshmen?"

"we're not kidnapping freshmen," bonnie remonstrated; "we're teaching them manners. it's my duty to protect my little cousin."

"you can come with us and help detect," said priscilla, generously.

"thank you," said patty, loftily. "i haven't time to play with you children. cathy fair and i are going to do old english to-night."

that evening, as patty, keyed to the point of grappling with and throwing whole pages of "beowulf," stood outside the chapel door waiting for cathy to appear, the professor of latin came out with a stranger.

"oh, miss wyatt!" she exclaimed in a relieved tone, pouncing upon patty. "i wish to present you to miss henderson, one of our alumnæ who is to lecture to-night before the archæological society. she has not been back for several years, and wishes to see the new buildings. have you time to show her around the campus a little before the lecture begins?"

patty bowed and murmured that she would be most happy, and cast an agonized glance back at cathy as she led the lecturer off. as they strolled about, patty poured out all the statistics she knew about the various buildings, and miss henderson received them with exclamations of delighted surprise. she was rather young and gushing for a ph.d. and an archæologist, patty decided, and she wondered desperately how she could dispose of her and get back to "beowulf" and cathy.

they rounded the top of a little hill, and miss henderson exclaimed delightedly,"there is the lake, just as it used to be!"

patty stifled a desire to remark that lakes had a habit of staying where they used to be, and asked politely if miss henderson would like to take a row.

miss henderson thought that it would be pleasant; but she had forgotten her watch, and was afraid there would not be time.

patty glanced about vaguely for some further object of interest, and spied mildred connaught sauntering toward the lake. she had forgotten all about the sherlock holmes adventure, and she suddenly had an inspiration. be it said to her credit that she hesitated a moment; but the lecturer's next remark led to her own undoing. she was murmuring something about feeling like a stranger, and wishing that she might know the students informally and see a little of the real college life.

"it would be a pity not to gratify her when i can do it so easily," patty told herself; and she added out loud, "i am sure we have time for a little row, miss henderson. you walk on, and i will run back and get my watch; it won't take a minute."

"i wouldn't have you do that; it is too much trouble," remonstrated miss henderson.

"it's no trouble whatever," patty protested kindly. "i can take a cross cut, and meet you at the little summer-house where the boats are moored. it's straight down this path; you can't miss it. just follow that girl over there"; and she darted away.

the lecturer gazed dubiously after her a moment, and then started on after the girl, who cast a look over her shoulder and quickened her pace. it was growing quite dusky under the trees, and the lecturer hurried on, trying to keep the girl in sight; but she unexpectedly turned a corner and disappeared, and at the same moment two strange girls suddenly dropped into the path, apparently from the tree-tops.

"good evening," they said pleasantly. "are you taking a walk?"

the lecturer started back with an exclamation of surprise; but as soon as she could regain her composure, she replied politely that she was strolling about and looking at the campus.

"perhaps you would like to stroll with us?" they inquired.

"thank you, you are very kind; but i have an engagement to row with one of the students."

priscilla and bonnie exchanged delighted glances. they had evidently caught a resourceful young person.

"oh, no; it's too late for a row. you might get malaria," priscilla remonstrated. "come and sit on the fence with us and admire the stars; it's a lovely night."

the lecturer cast an alarmed glance toward the fence, which appeared to have an unusually narrow top rail. "you are very kind," she stammered, "but i really can't stop. the girl will be waiting."

"who is the girl?" they inquired.

"i don't know that i remember her name."

"mildred connaught?" bonnie suggested.

"no; i don't think that is it, but i really can't say. i have only just met her."

miss henderson was growing more and more puzzled. in her day the students had not been in the habit of way-laying strangers with invitations to go walking and sit on fences.

"ah, do stay with us," bonnie begged, laying a hand on her arm. "we're lonely and want some one to talk to—we'll tell you a secret if you do."

"i am sorry," miss henderson murmured confusedly, "but—"

"we'll tell you the secret anyway," said bonnie, generously, "and i'm sure you'll be interested. the sophomores are going to have their tree ceremonies to-night!"

"and you know," priscilla broke in, "that the freshmen really ought to attend them too—it doesn't matter if they aren't invited. but where do you suppose the freshmen are to-night? they're attending a foolish little lecture on the roman forum."

"and though we don't wish to seem insistent," bonnie added, "we should really like to have your company until the lecture is over."

"until the lecture is over! but i am the lecturer," gasped miss henderson.

bonnie grinned delightedly. "i am happy to meet you," she said, with a bow. "and perhaps you do not recognize us. i am mr. sherlock holmes, and this is my friend dr. watson."

dr. watson bowed, and remarked that it was an unexpected pleasure. he had often heard of the famous lecturer, but had never hoped to meet her.

miss henderson, who was not very conversant with recent literature, looked more dazed than ever. it flashed across her mind that there was an insane asylum in the neighborhood, and the thought was not reassuring.

"we'll not handcuff you," said bonnie, magnanimously, "if you'll come with us quietly."

the lecturer, in spite of fervid protestations that she was a lecturer, presently found herself sitting on the fence, with a girl on either side grasping an elbow. a light was beginning to break upon her, together with a poignant realization of the fact that she was seeing more of the real college life than she cared for.

"what time is it?" she asked anxiously.

"ten minutes past eight by my watch, but i think it's a little slow," said bonnie.

"i am afraid you're going to be late for your lecture," said priscilla. "it seems a pity to waste it. suppose you tell it to us instead."

"yes, do," urged bonnie. "i just dote on the roman forum."

the lecturer preserved a dignified silence, which was broken only by the croaking of the frogs and the occasional remarks of the two detectives. she had relinquished all hope of ever seeing the archæological society, and had philosophically resigned herself to the prospect of sitting on the fence all night, when suddenly there burst out from across the campus a song of victory, mingled with cheers and inarticulate yells.

at the first sound, bonnie and priscilla tumbled down from the fence, bringing the lecturer with them, and, each grasping her by a hand, they started to run. "come on and see the fun," they laughed. "you're perfectly welcome; it's no secret any more." and, in spite of breathless protestations that she much preferred to walk, miss henderson found herself dashing across the campus in the direction of the sounds.

heads suddenly appeared in the dormitory windows, doors banged, and girls came running from every quarter with excited exclamations: "the sophomores are having their tree ceremonies!" "where are the freshmen?" "why didn't they get there?"

a crowd quickly gathered in the shadow of the trees and watched the scene with laughing interest. a wide circle of colored lanterns swayed in the breeze, and, within, a line of white-robed figures wound and unwound about a tiny tree to the music of a solemn chant.

"isn't it pretty? aren't you glad we brought you?" bonnie demanded as they pushed through the crowd.

the lecturer did not answer, for she caught sight of the latin professor hurrying toward them.

"miss henderson! i was afraid you were lost. it is nearly half-past eight. the audience has been waiting, and we have been filling in the time with reports."

for a moment the lecturer was silent, being occupied with an amused scrutiny of the faces of her captors; and then she rose to the occasion like a lady and a scholar, and delivered a masterly apology, with never a reference to her sojourn on the fence.

bonnie and priscilla stared at each other without a word, and as miss henderson was led away to the remnants of her audience patty suddenly appeared.

"good evening, mr. sherlock holmes and dr. watson. did you solve your mystery?" she asked sweetly.

priscilla turned her to the light and scrutinized her face.

patty smiled back with wide-open, innocent eyes.

priscilla knew the expression, and she shook her. "you little wretch!" she exclaimed.

patty squirmed out from under her grasp. "if you remember," she murmured, "i once said that the lick observatory was in dublin, ireland. it was a very funny mistake, of course, but i know of others that are funnier."

"what do you mean?" bonnie demanded.

"i mean," said patty, "that i wish you never to mention the lick observatory again."