Moriarty did not care to suppose anything so unpleasant.

Mr Dexter was still prowling about on the junior gravel, when the two Irishmen ran round and across the senior gravel to the gymnasium. Here they put in a few minutes’ gentle sparring, and then marched boldly up to Mr Day (who happened to have looked in five minutes after their arrival) and got their paper.

“What time did O’Hara and Moriarty arrive at the gymnasium?” asked Mr Dexter of Mr Day next morning.

“O’Hara and Moriarty? Really, I can’t remember. I know they left at about a quarter to seven.”

That profound thinker, Mr Tony Weller, was never so correct as in his views respecting the value of an alibi. There are few better things in an emergency.

XVIII

O’HARA EXCELS HIMSELF

It was Renford’s turn next morning to get up and feed the ferrets. Harvey had done it the day before.

Renford was not a youth who enjoyed early rising, but in the cause of the ferrets he would have endured anything, so at six punctually he slid out of bed, dressed quietly, so as not to disturb the rest of the dormitory, and ran over to the vault. To his utter amazement he found it locked. Such a thing had never been done before in the whole course of his experience. He tugged at the handle, but not an inch or a fraction of an inch would the door yield. The policy of the Open Door had ceased to find favour in the eyes of the authorities.

A feeling of blank despair seized upon him. He thought of the dismay of the ferrets when they woke up and realised that there was no chance of breakfast for them. And then they would gradually waste away, and some day somebody would go down to the vault to fetch chairs, and would come upon two mouldering skeletons, and wonder what they had once been. He almost wept at the vision so conjured up.