Marjorie looked out to sea with a puzzled expression.
'I don't know,' she said at last, with a little laugh; 'except that it's such fun knowing that we've got a secret!'
'I've been thinking,' said Allan, who was lying full length upon a ridge and looking towards Inchkerra, 'while we are having such a jolly time of it over here, what must be the feelings of the man who stole those letters, now he knows that the police are after him!'
The others all looked towards the island, where they could see the low, grey cottages of the little village.
'It seems strange that they haven't got him yet,' observed Marjorie.
'I met MacLean the constable from Stornwell this morning,' said Hamish, 'and he told me that they had no trace as yet, and that they believed it must have been done by some stranger who came over from the mainland, and got away immediately after the robbery.'
'I hope so,' said Allan; 'it isn't nice to think of any of our people being dishonest.'
'If it was a stranger,' said Reggie; 'they may never catch him.'
'I heard father say that he would be traced by the money-orders,' replied Allan. 'It seems that there were several post-office orders in a registered letter addressed to father, and that is one of the letters that is missing. Father says that the thief is sure to try to make use of the orders sooner or later, and they have sent the numbers to every post-office in the kingdom.'
'And then the man will be caught!' said Tricksy in an awestruck tone.