"I'll tell you why I don't. Because in this "ere realm of liberty, and Britannia ruling the waves, you ain't allowed to arrest a chap on suspicion, even if you know puffickly well who done the job."

"What a shame!" said Jimmy warmly. "And who do you think did it?"

"I don't think I know." Johnson's voice was ponderous as his boots.

"It's a man what's known to the police on account of a heap o crimes he's done, but we never can't bring it "ome to "im, nor yet get sufficient evidence to convict."

"Well, said Jimmy, "when I've left school I'll come to you and be apprenticed, and be a detective. Just now I think we'd better get home and detect our supper. Good night!"

They watched the policeman's broad form disappear through the swing door of the police-station; and as it settled itself into quiet again the voice of Gerald was heard complaining bitterly.

"You've no more brains than a halfpenny bun," he said; "no details about how and when the silver was taken."

"But he told us he knew," Jimmy urged.

"Yes, that's all you've got out of him. A silly policeman's silly idea.

Go home and detect your precious supper! It's all you're fit for."

"What'll you do about supper?" Mabel asked.

"Buns!" said Gerald, "halfpenny buns. They'll make me think of my dear little brother and sister. Perhaps you've got enough sense to buy buns? I can't go into a shop in this state."

"Don't you be so disagreeable," said Mabel with spirit.

"We did our best. If I were Cathy you should whistle for your nasty buns."

"If you were Cathy the gallant young detective would have left home long ago. Better the cabin of a tramp steamer than the best family mansion that's got a brawling sister in it," said Gerald. "You are a bit of an outsider at present, my gentle maiden. Jimmy and Cathy know well enough when their bold leader is chaffing and when he isn't.

"Not when we can't see your face we don't," said Cathy, in tones of relief. "I really thought you were in a flaring wax, and so did Jimmy, didn't you?"

"Oh, rot!" said Gerald. "Come on! This way to the bun shop."

They went, And it was while Cathy and Jimmy were in the shop and the others were gazing through the gla.s.s at the jam tarts and Swiss rolls and Victoria sandwiches and Bath buns under the spread yellow muslin in the window, that Gerald discoursed in Mabel's ear of the plans and hopes of one entering on a detective career.

"I shall keep my eyes open tonight, I can tell you," he began. "I shall keep my eyes skinned, and no jolly error. The invisible detective may not only find out about the purse and the silver, but detect some crime that isn't even done yet. And I shall hang about until I see some suspicious-looking characters leave the town, and follow them furtively and catch them red-handed, with their hands full of priceless jewels, and hand them over."

"Oh!" cried Mabel, so sharply and suddenly that Gerald was roused from his dream to express sympathy.

"Pain?" he said quite kindly. "It's the apples they were rather hard."

"Oh, it's not that," said Mabel very earnestly. "Oh, how awful! I never thought of that before."

"Never thought of what?" Gerald asked impatiently.

"The window."

"What window?"

"The panelled-room window. At home, you know at the castle.

That settles it I must go home. We left it open and the shutters as well, and all the jewels and things there. Auntie'll never go in; she never does. That settles it; I must go home now this minute."

Here the others issued from the shop, bun-bearing, and the situation was hastily explained to them.

"So you see I must go," Mabel ended.

And Kathleen agreed that she must.

But Jimmy said he didn't see what good it would do. "Because the key's inside the door, anyhow."

"She will be cross," said Mabel sadly. "She'll have to get the gardeners to get a ladder and "

"Hooray!" said Gerald. "Here's me! n.o.bler and more secret than gardeners or ladders was the invisible Jerry. I'll climb in at the window it's all ivy, I know I could and shut the window and the shutters all sereno, put the key back on the nail, and slip out unperceived the back way, threading my way through the maze of unconscious retainers. There'll be plenty of time. I don't suppose burglars begin their fell work until the night is far advanced."

"Won't you be afraid?" Mabel asked. "Will it be safe suppose you were caught?"

"As houses. I can't be," Gerald answered, and wondered that the question came from Mabel and not from Kathleen, who was usually inclined to fuss a little annoyingly about the danger and folly of adventures.

But all Kathleen said was, "Well, good-bye; we'll come and see you tomorrow, Mabel. The floral temple at half-past ten. I hope you won't get into an awful row about the motor-car lady."

"Let's detect our supper now," said Jimmy.

"All right," said Gerald a little bitterly. It is hard to enter on an adventure like this and to find the sympathetic interest of years suddenly cut off at the meter, as it were. Gerald felt that he ought, at a time like this, to have been the centre of interest. And he wasn't. They could actually talk about supper. Well, let them. He didn't care! He spoke with sharp sternness: "Leave the pantry window undone for me to get in by when I've done my detecting.

Come on, Mabel." He caught her hand. "Bags I the buns, though,"

he added, by a happy afterthought, and s.n.a.t.c.hing the bag, pressed it on Mabel, and the sound of four boots echoed on the pavement of the High Street as the outlines of the running Mabel grew small with distance.

Mademoiselle was in the drawing-room. She was sitting by the window in the waning light reading letters.

"Ah, vous voici!" she said unintelligibly. "You are again late; and my little Gerald, where is he?"

This was an awful moment. Jimmy's detective scheme had not included any answer to this inevitable question. The silence was unbroken till Jimmy spoke.

"He said he was going to bed because he had a headache." And this, of course, was true.

"This poor Gerald!" said Mademoiselle. "Is it that I should mount him some supper?"

"He never eats anything when he's got one of his headaches,"

Kathleen said. And this also was the truth.

Jimmy and Kathleen Went to bed, wholly untroubled by anxiety about their brother, and Mademoiselle pulled out the bundle of letters and read them amid the ruins of the simple supper.

"It is ripping being out late like this," said Gerald through the soft summer dusk.

"Yes," said Mabel, a solitary-looking figure plodding along the high-road. "I do hope auntie won't be very furious."

"Have another bun," suggested Gerald kindly, and a sociable munching followed.

It was the aunt herself who opened to a very pale and trembling Mabel the door which is appointed for the entrances and exits of the domestic staff at Yalding Towers. She looked over Mabel's head first, as if she expected to see someone taller. Then a very small voice said:

"Aunt!"