'You see, Miss Marjorie,' continued Euan, 'Neil made no secret of having sent off a post-office order that day. He had got one on the evening before, when he was at the MacAlisters', and he put it in the pocket of his reefer jacket. You know that new churn he got for his mother? Well, he was paying for that by instalments and this was one of the payments. The day after the robbery, he went into the post-office, got the order, put it into an envelope containing a note to say that he hoped to send the last instalment next week, and sent it away. But the order that came out of the letter was not the one that he bought at Mrs. MacAlister's that night; and the curious thing is, that he found the order that he believed he had sent away, still in his coat pocket when he went to look. At least that's the story he tells, poor lad.'

'Then,' said Allan, 'how do you account for the wrong order being in the letter?'

Euan pondered a minute, and then said, 'Mr. Allan, there's only one explanation of it, so far as I can see. Some person must have been trying to screen himself by throwing suspicion on to Neil. You say that there was more than one order in the laird's letter?'

'Yes,' replied Allan, 'and they don't seem to have heard anything about the others yet.'

'They will turn up some day, no doubt, and then the whole matter may be cleared up; but in the meanwhile there's nothing to go by to help the poor lad. Perhaps they may be traced before the case comes up in Edinburgh.

'Oh, I hope so,' cried the girls, 'and then they'll get their finger on the real culprit?'

'The person who did it must have put the order into Neil's pocket,' said Allan. 'How could they have managed it and what would make them think of Neil?'

'Well, Mr. Allan; you know how these country post-offices are kept. The letter-box is in the MacAlisters' kitchen, which is at the same time their shop, and where every one goes in and out. The box is never locked; and after the letters are sorted they often lie on the table for hours, waiting until the postman comes to take them away. Any one who was not honest could easily slip into the kitchen when Mrs. MacAlister's back was turned and do what they liked with the letters; but such a thing has never happened before. Now, whoever committed the robbery has seen that Neil was in the post-office that evening, turning over the letters; and he saw that Neil got a money order to send away. All this made him think that Neil was the one to fasten the guilt on to, so after breaking into the post-office that night he slipped into the house, unknown to Neil or his mother, and put the order where Neil was likely to take it for his own.'

Allan nodded approvingly when the coastguard paused in what was an unusually long effort for him.

There's something in that,' he said. 'But who would have done such a thing?'