“And can’t you possibly go, dear?” she asked entreatingly.

I think only one man was ever known to pull the cord which set in motion a guillotine that took off his own head.  But there is much unknown, as well as unwritten, history.

“Not without neglecting some work which I ought to do to-day,” he said.

“I think you care more for your work sometimes than you do for me.”  There was a little quaver in her voice as she spoke.  “And I wish you’d stop behaving as if I were your daughter.  I don’t know what ails you this morning; but if you go on this way I shall call you Professor Silex all the time.  How would you like that?”

A passionate exclamation rose to his lips, and died there.  A spasm of bitter pain made his face for a moment hard and stern.  Then he smiled, and said gently, “I should not like it at all, as you know very well.  But I must go now, or I shall be late for my class.  Good-by, dear child.”  And, parting her soft, curling hair, he pressed a fatherly kiss upon her forehead.

She threw her arms about his neck, crying, “No!—­on my lips.”  And, pressing an eager kiss upon his mouth, she added, “There! that is a sealing, a fresh sealing, of our engagement; and I wish—­oh, how I wish!—­that we were to be married to-morrow—­to-day!”

The professor gently disengaged himself from her clinging arms, saying, still with a smile, “But I thought the wedding-gown was still to make?  Good-by.  I will come early this evening and hear all about the enchanted island.”

For the expedition which had been planned by the three for that afternoon was to explore a little island far down the river, farther than any of them had yet gone.

Rosamond wore no roses when she went slowly down the bank that day,—­not even in her cheeks.

And when Louis Symington saw her coming alone, only the sunbrown on his face concealed the sudden rush of blood from it to his heart.

“The professor could not come,” she said hurriedly, “so he made me come without him; that is—­I mean—­” And she stopped, confused.

“If you prefer to wait until he can go with us, pray do not hesitate to say so,” he replied stiffly, and pausing—­with her hand in his—­in the act of helping her into the boat.

“Oh, I did not mean to say anything rude,” she exclaimed penitently; and she stepped across the seats to the cushioned end of the boat.  “Of course we will go; but perhaps—­would you mind—­couldn’t we just take a little row to-day, and save the island until the professor can go?”

“Certainly,” he said, still in the same constrained tone; and, without another word, he helped her to her place and arranged the cushions about her.

The silence lasted so long that she felt she could bear it no longer.

“Will you please sing something?” she said at last, desperately, “You know you sang that first day; and it sounded so lovely on the water.  Do you remember?”