‘We haven’t identified the hairpins for certain,’ said Peter, comfortingly. ‘That will be a little task for Miss Vane.’ He gathered up the papers. ‘I’ll take these and add them to the dossier. I suppose there’s no message for us on the blackboard?’
He picked up the board, which contained only a few chemical formulæ, scribbled in chalk, in Miss Edwards’s handwriting, and restored the easel to an upright position, on the far side of the window.
‘Look!’ said Harriet, suddenly. ‘I know why she went round that way. She meant to get out by the lecture-room window, and had forgotten the bars. It was only when she pulled the curtain aside and saw them that she remembered the dark-room and plunged away in a hurry, knocking over the blackboard and tumbling into the chairs on the way. She must have
