"You surely won't let this sort of thing drive you away?" said Armstrong.

"What's to be done, then? They first monkey with the boat--by Jove!

they may have cut her loose again."

"No, I spy her nose," said Pratt. "They believe in variety, evidently.

But I quite agree with you. We shall always have to leave one on guard, and that will spoil the trio. Two's company, three's fun. All the same, the position is so jolly interesting that I shouldn't like to go right away and leave the mystery unsolved--I mean their objection to our company. We haven't had the cold shoulder anywhere else; and here, first old Crawshay, then these unknown--look here, you fellows, I vote we take the job up in earnest, and get to the bottom of it. It will alter the Arcadian simplicity of our holiday, but for my part I'd risk any amount of brain f.a.g over a good jigsaw puzzle like this."

"We'll think it over," said Warrender. "The princ.i.p.al thing is not to lose my boat, and the hundred odd pounds she cost."

On their way down to the river, Pratt espied a greyish object sticking in a bush. Shaking it down, he picked up a broken cardboard box on which was printed a description of "Best quality tin-tacks: British made."

"A clue!" he cried. "Sherlock Holmes would have built a whole theory on this. I don't think I was cut out for diplomacy after all. Criminal investigation is my forte. I'll go down to remote posterity as the most brilliant detective of this Pratt lost no time in taking a first step in his new career. At breakfast Warrender suggested that the tent had better be removed from its surrounding of tacks, which were too numerous to be easily collected.

"Very well," said Pratt. "You and Armstrong are the hefty men. You won't want my help, so I'll scull the dinghy up to the ferry, and start my investigations."

"Don't talk too much," said Armstrong.

"My dear chap, speech was given us to conceal thought. There's an art, some ancient said, in concealing art, and I bet I'd say more and tell less than any old Prime Minister that ever lived."

Leaving the dinghy in charge of the ferryman, he smiled a greeting to Rogers, the innkeeper, whose jolly face he caught sight of at the window, walked on to the village, and entered the general dealer's shop.

"Fine morning," he said to the ap.r.o.ned youth in attendance. "D'you happen to have any tenpenny nails?"

"We've got some nails three a penny, sir."

"No good at all. You couldn't hang a pirate on one of those, I'm sure.

I suppose the tenpenny nail has gone out of fashion, but perhaps you have some tin-tacks. I dare say they'll do as well."

"Ay, we've got some tin-tacks--two sorts, white and blue."

"Not red?"

"No; I don't know as ever I seed 'em red."

"Well, I particularly wanted red; they don't show their blushes, you know. If you haven't, you haven't. I'll try blue; they won't look any bluer however hard you hit 'em." The a.s.sistant, staring at him like an amazed ox, handed him a box. "Yes," he went on, "now I look at them, I couldn't wish for better. They're a most admirable shade of blue, and exactly match my Sunday socks. I don't suppose there's much demand for 'em; my hosier a.s.sured me my socks were a very special line, so, of course, there couldn't be many people wanting tacks of that colour. I dare say you haven't sold a box of these since last season."

"Ah, but we have," said the simple youth, catching at something at last within his comprehension. "Only yesterday one of they furriners up at Red House bought three boxes."

"You don't say so! What an appet.i.te he must have! I suppose it was that big fellow who talks through his nose? He wears a red waistcoat, so I dare say he has blue socks."

"It warn't him. He's the groom. 'Twas the gardener chap."

"Of course. What was I thinking of? He wanted them to tack up his vines. They wouldn't be any good for horse-shoes, and there's no question of socks at all. You needn't wrap it up, the box won't catch cold in my pocket. Sixpence ha'penny? Dirt cheap. I think they're worth quite a guinea a box, but you daren't charge that, of course, or they would haul you up as profiteers. Thanks so much."

He had noticed that the full box exactly matched the broken one taken from the bush.

Elated at the success of his first move, Pratt returned at once to the camp.

"You're soon back," said Warrender. "Changed your mind again?"

"Not a bit. I'm inclined to think diplomats and detectives are of one kidney. I've been magnificently diplomatic, and I've made a discovery."

"Well?"

"My old uncle's as mad as a hatter!"

"A family failing," Armstrong remarked. "But what's that to do with it?"

"Why, this, old tomato. He employs a lot of foreigners; that's mad, to begin with. He goes away, and leaves them in the house with instructions to sow tin-tacks on No Man's Island. If that isn't stark madness, I'd like to know what is."

"Hadn't you better tell us plainly what you've been about?" said Warrender.

"In words of one syllable. I bought a box of tin-tacks. Here it is, and here's the one we found in the bush. You see, they're twins. They were bought at the same shop, to wit, the one owned by Samuel Blevins, general dealer and banjoist, I understand. My uncle's gardener bought three yesterday. Now, I ask you, would any man's gardener sprinkle inoffensive campers with tin-tacks unless instructed to? It's all as plain as a pikestaff. My mad uncle has a morbid horror of trespa.s.sers.

He leaves word that they are to be chevied away by means fair or foul----"

"But No Man's Island isn't his," Warrender interrupted.

"Certainly. That proves his madness. He thinks anybody who gets a footing here has designs on his property. It's a sort of Heligoland.

He employs an ex-poacher to guard his own domains, and the foreigners to clear his outpost. Nothing could be plainer."

"Rot!" exclaimed Armstrong.

"Have it your own way. The facts are undeniable. Rush and the foreigners are in league to get rid of us, and they can't have any motive except their master's interest."

"We don't know that," said Warrender. "Your imagination runs too fast, young man. We don't even know for certain that Rush and the foreigners are working together. All we really know is that some one wants to make the place too uncomfortable for us. The question is, what shall we do?"

"Stick it," said Armstrong. "It means keeping watch by night; we can take turns at that. We'll soon find out if----"

"Ahoy, there!" cried a voice from the river.

Unperceived, a skiff had run in under the bank, and its occupant, a stout old gentleman in flannels, was stepping ash.o.r.e.

"Old Crawshay!" murmured Pratt.

They got up to meet their visitor.

"Good-morning, my lads," said he, genially. "Surprised to see me, I dare say. We didn't part on the best of terms, but--well, let's shake hands and forget all about that. My daughter told me that you very kindly came to her a.s.sistance the other day. I'm obliged to you. I'm only sorry it didn't happen before we--but there, that's wiped up, isn't it?

If you knew how I'd been pestered! By the way, one of you is related to my neighbour across the river, I understand."

"Yes, sir, that's me," said Pratt. "We're not on calling terms, though."

"Neither am I," rejoined Mr. Crawshay, with a smile. "We don't hit it together. He's a little----"

"Potty, sir," said Pratt, as the old gentleman caught himself up. "It's a sore trial to the rest of the family. We were only talking about his distressing affliction just before you came. He really ought to be shut up."

"Indeed! I wasn't aware that it was as bad as that. That is certainly very distressing."

"A most unusual form of mania, too. I never heard anything like it before. Of course, there are people who crab their own country and countrymen, but it's more talk than anything else. My poor uncle, however, goes so far as to employ foreigners, who stick tin-tacks into people."