jerk the string, the cotton will break, then down will plump the rat right on to their chests," said Lindsay, justly proud of her inventive powers. "Poke the box under the valance, Cicely, quick! I thought I heard someone coming."

The cardboard box contained a bobbin, to which a second string was tied, and concealed in the same manner as the first.

"I don't believe they'll suspect anything," said Cicely. "Won't it be lovely to give them a scare!"

At bedtime the conspirators retired innocently as usual, having wished Beryl and Effie good night in the passage.

"I nearly said I hoped nothing would disturb them," laughed Lindsay, "but I thought it would be wiser not. How long must we leave them to go to sleep?"

"About half an hour, I should think. Let us get up as soon as we hear the clock in the picture gallery striking nine."

The twilight lasted long, so it was still quite possible to distinguish objects as two nightgowned, barefooted figures stole gently across the landing. Fortunately everything was perfectly quiet in the upper portion of the house. The younger girls were in bed, and the elder ones were with the teachers downstairs.

"We must be sure to work the right strings," breathed Lindsay. "Have you got yours? This was mine, with a knot at the end."

She gave a smart pull, and the bobbin rattled loudly inside the box. They could hear it plainly, even through the closed door.

"What is that?"

The question came in an anxious and wideawake tone from within the room.

"I don't know. Oh, there it is again!"

The voice this time was Effie's.

"It sounds as if it were under the bed!"

"Oh, surely it's not a rat!"

"Now for it!" whispered Cicely, pulling the second string.

The result was all they could have desired. A series of yells proceeded from the four-post bed, sufficient not only to rouse the occupants of the other rooms on the landing, but to bring Miss Frazer hurrying up from the library. Lindsay and Cicely dropped their strings and fled, not a second too soon. They could hear Miss Frazer striking a match to light the candle, and her exclamation when she discovered the cause of the uproar.

"All the girls have turned out to see what's the matter," said Cicely. "If you and I don't go too, they'll know who's done it."

"I think we shall have to own up, in any case," replied Lindsay.

"It was worth the scolding," she declared afterwards, when Miss Frazer had administered a due homily on the danger of practical jokes. "I only wish I could have seen their faces when the rat plumped on to them. They needn't talk of screaming at nothing, and if they ever begin to tease us about anything again—well, we'll just say 'Rats!'"