"The Kenneth Digby case. I'm expecting him here every minute, but I've nothing new to tell him."

"Kenneth Digby?" echoed Cleek, a little pucker between his brows. "Any relation to the soldier and scientist-inventor of that new machine-gun tried out last year?"

"His son, Cleek. And, as his father is practical guarantee of his integrity and uprightness, you can imagine what a blow this has been to Colonel Digby and his family."

"A blow! Does that mean you are trying to tell me that Graham Digby's son is a traitor to his country?" flung back Cleek in rising tones of amazement. "Suppose you give me all the facts, old man—just what has happened."

"It's like this, Cleek," answered Mr. Narkom. "Young Digby is engaged in laboratory experiments with high explosive; trying, as far as I can gather, to evolve a smokeless powder—— Good heavens, what's wrong?" For his famous associate was sitting erect in his seat, his eyes sparkling and brilliant, his brows twitching with excitement, his breath coming in gasps.

"Smokeless? Is that the secret? Blithering idiot I was! Of course, a child would have guessed it. But go on, old man. Don't mind me. I've been reading the papers, and am just beginning to see."

"Well, it's more than I am," ejaculated Mr. Narkom, blankly. "However, to continue: it seems that as fast as Digby evolves a formula our Secret Service reports to the War Office that it is known immediately to a certain unfriendly foreign power. Well, Digby is nearly frantic, and is to be here again at 11 o'clock."

"H'm, it's that now," said Cleek, as he glanced out of the window, "and unless I am mistaken here he comes. Introduce me as Lieutenant Deland in mufti, will you? I'll have a look into things for myself, directly I have made a few necessary changes."

And that was why a minute or two elapsed before, after a brief word on the house 'phone, Captain Digby was shown in. He was a fine, upstanding, manly-looking young soldier of about eight and twenty, a man with something of the scholar's refinement in his bearing. But this morning he was nearly as hysterical as a schoolgirl.

"Oh, Mr. Narkom, help me! For God's sake, solve this mystery!" he cried as he gripped Mr. Narkom's outstretched hand in his own and pressed it excitedly. "My father said everything would be all right just as soon as you had the matter in your hands—but it's gone, another! The horror and disgrace of it! I shall kill myself in the end!"