While posing both as an Englishman and a Russian, John Mindiggle was neither. He was a German—a Secret Service agent—whose work was entirely for the futherance of Kaiserism. During twenty years of practically continuous residence in Great Britain Ernst von Verbrennungsraum had been working unostentatiously, yet deliberately, for the Fatherland, for the day when Germany would become the mistress of the World and when freedom would be denied to all other nations large or small.

Von Verbrennungsraum's chance came when Russia took the suicidal step of exchanging the yoke of Czardom for that of unbridled "liberty". The first revolution that resulted in the abdication of the Czar Nicholas was a step in the right direction so far as Germany was concerned, but it was not far enough. The new republic still maintained an army on its Austro-German frontier—an army in which bravery and cowardice existed cheek by jowl. Utter internal chaos was what was desired in order to remove a menace to Germany's eastern frontier and thus enable her to throw thousands of troops into other sectors of battle.

To compass the downfall of the Kerensky regime the anarchists were to resort to a favourite device—explosives. In a secret laboratory was manipulated a new and extremely powerful chemical, which, in its final state, resembled, and could hardly be distinguished from, cut diamonds. It was a sample of this diabolical stuff that Mindiggle was in hopes of sending to Petrograd through the agency of Noel Fordyce.

Impossible to detonate by combustion, friction, or the application of heat, the explosive was perfectly safe to handle until the temperature fell below -5° C. The moment the mercury dropped to that point the explosive would simultaneously and spontaneously act.

In his attempt to induce Fordyce to convey the "diamonds" to Russia the German agent was employing a double-barrelled weapon. If the stuff did get to Petrograd well and good. If, on the other hand, the temperature on board the submarine should fall below -5° C. while running awash towards the port of Cronstadt, it meant utter annihilation to R19 and terrific damage to everything within a mile of the source of the explosion.

And, confident in his ability to make use of Flirt as the deciding factor, von Verbrennungsraum duly applied for and obtained a summons against Noel Fordyce.

CHAPTER III

The Sub's Stratagem

Ernst von Verbrennungsraum had not taken into account one of Noel Fordyce's characteristics—that of grim, almost obstinate determination. Under the mistaken impression that, for the sake of his pet, the Sub would agree to his terms, the Secret Service agent applied for and obtained a summons.

"I'll fight him while I have a penny left to call my own," declared Fordyce, and with this laudable intention he engaged the best solicitor in Otherport.