In no city of the world is a crowd so quickly collected as in London; in none is one so easily satisfied and dispersed.  Within five minutes the detectives had hurried their three captives away towards the nearest cab-rank, and the people who had left their tea and their cakes to gather round, to stare, and to listen had gone back to their tables to discuss this latest excitement.  But the chief and Allerdyke, Fullaway and Appleyard, Miss Slade and Rayner stood in a little group on the grass and looked at each other.  Eventually, all looks except Rayner’s centred on Miss Slade, who, somewhat out of breath from her tussle, was settling her hat and otherwise composing herself.  And it was Miss Slade who spoke first when the party, as a party, found itself capable of speech.

“I don’t know who it was,” observed Miss Slade, rather more than a little acidly, “who came interfering in my business, but whoever he was he nearly spoilt it.”

She darted a much-displeased look at the chief, who hastened to exculpate himself.

“Not I!” he said with a smile.  “So don’t blame me, Miss Slade.  I was merely a looker-on, a passive spectator—­until the right moment arrived.  Do I gather that the right moment had not actually arrived—­for your purpose?”

“You do,” answered Miss Slade.  “It hadn’t.  If you had all waited a few moments you would have had all three men in conference round one of those tables, and they could have been taken with far less fuss and bother—­and far less danger to me.  It’s the greatest wonder in the world that I’m not lying dead on that grass!”

“We are devoutly thankful that you are not,” said the chief fervently.  “But—­you’re not!  And the main thing is that the three men are in custody, and as for interference—­”

“It was Chilverton,” interrupted Fullaway, who had been staring at his mysterious secretary as if she were some rare object which he had never seen before.  “Chilverton!—­all Chilverton’s fault.  As soon as he set eyes on Van Koon nothing would hold him.  And what I want to know—­”

“We all want to know a good deal,” remarked the chief, glancing invitingly at Miss Slade.  “Miss Slade has no doubt a good deal to tell.  I suggest that we walk across to those very convenient chairs which I see over there by the shrubbery—­then perhaps—­”

“I want to know a good deal, too,” said Miss Slade.

“I don’t know who you are, to start with, and I don’t know why Mr. Appleyard happens to be here, to end with.”

Appleyard answered these two questions readily.

“I’m here because I happen to be Mr. Allerdyke’s London representative,” he said.  “This gentleman is a very highly placed official of the Criminal Investigation Department.”

Miss Slade, having composed herself, favoured the chief with a deliberate inspection.

“Oh! in that case,” she remarked, “in that case, I suppose I had better satisfy your curiosity.  That is,” she continued, turning to Rayner, “if Mr. Rayner thinks I may?”