The next day Diana entered upon her work,--and for a fortnight following she was kept fully employed. But nothing mysterious, nothing alarming or confusing to the mind was presented for her contemplation or co-operation. Not once was she called upon to enter the laboratory where the strange wheel whirled at the bidding of the influence of light, going faster or slower, according to the ascension or declension of the sun; and not once did Dimitrius refer to the subject of his discourse with her on that first moonlight night of her arrival. Her knowledge of Latin and Greek stood her in good stead, for she was set to translate some musty rolls of vellum, on which were inscribed certain abstruse scientific propositions of a thousand years old,--problems propounded by the Assyrians, and afterwards copied by the Latins, who for the most part, had left out some of the original phraseology, thereby losing valuable hints and suggestions, which Dimitrius was studying to discover and replace. Diana was a careful, clever, and devotedly conscientious worker; nothing escaped her, and she shirked no pains to unravel the difficulties, which to less interested students, might have seemed insuperable. Much as she desired to know more of Dimitrius himself and his own special line of research, she held her peace and asked no questions, merely taking his instructions and faithfully doing exactly as she was told. She worked in the great library where he had at first received her, and where the curious steel instrument she had noticed on entering, swung to and fro continuously, striking off a pin’s point of fire as it moved. Sometimes in the pauses of her close examination of the faded and difficult Latin script on which all her energies were bent, she would lift her eyes and look at this strange object as though it were a living companion in the room, and would almost mentally ask it to disclose its meaning; and one morning, impelled by a sudden fancy, she put her watch open on the table, and measured the interval between one spark of fire and the next. She at once found that the dots of flame were struck off with precision at every second. They were, in fact, seconds of time. “So that, if one had leisure to watch the thing,” she mused, “one would know that when sixty fire-flashes have flown into air, one minute has passed. And I wonder what becomes of these glittering particles?”