As has been before explained, the members of the Fourth and Fifth Forms--nineteen girls in all--slept in the huge chamber which occupied an entire wing of the house, and had been the dormitory of the French nuns a hundred years ago. The small room at the end, formerly the cell of the Mother Superior, was now the bower of Miss Gibbs. It had two doors, one leading into the passage and another into the dormitory, so that she could keep an eye upon the nineteen inmates. It was a very unnecessary arrangement to have her so near, the girls considered, for she would come popping in immediately if they made a noise. They envied the Sixth, who slept in little bedrooms along the corridor, and wished Miss Gibbs had possessed a lesser sense of duty and a greater appreciation of luxury, so that she might have chosen a more comfortable and spacious bedroom elsewhere. When sufficient tin-can ammunition had been prepared, Raymonde carried the baskets upstairs by stealth, and hid them in the lumber cupboard which she had discovered on the day she had explored the roof. They were not likely to be disturbed here, for probably no one save herself knew of the existence of the tiny room. She crept through the small door on to the tiles, and verified her position by cautious tapping, to which Morvyth, stationed in the passage below with a hockey stick, replied. Having thus taken her exact bearings, she felt that the whole plot was in good training. "We must choose a moonlight night, or I shouldn't be able to see my way over the roof," she informed the committee. "Of course Zepps don't generally come when there's a moon, but there'll be no time for anybody to think of that. You know your part of the business?" "Ra--ther!" The household at the Grange retired early to rest. Miss Gibbs, who was an ardent advocate of daylight saving, and always rose at six, was generally in bed by eleven, on the theory that it is impossible to burn a candle at both ends. As a rule, every occupant of the long dormitory was wrapt in slumber before that hour, and the mistress, taking a last peep at the rows of small beds, would hear nothing but peaceful breathing. On one particular evening, however, when she made her usual survey of the room, seven of the apparent sleepers were foxing. They lay with closed eyes and composed faces, but inwardly they were particularly lively. Each one had solemnly passed her word to keep awake, and considered herself on sentry duty. To pass the time they had brought acid drops to bed with them, and sucked them slowly, so as to make them last as long as possible. They dared not talk, for fear of disturbing the others, though the temptation was great. Occasionally a stealthy hand would reach over to the next bed, to make sure of its occupant's vigilance, and the squeeze would be passed on down the row of seven.