When Orloff pursued the luckless Klostivitch it must be remembered that he left the attic window open. In the room was stored a small quantity of the powerful nitro-talcite, the temperature of the house being kept up by means of the central heating-stove. Upon the house being abandoned the neglected fires soon dwindled, while the temperature of the attic fell so steadily that within half an hour of the time of leaving the house the nitro-talcite automatically exploded. Most of the buildings in the Bobbinsky Prospekt were blown to atoms and considerable damage done to the adjoining property; but, as "it's an ill wind that blows nobody any good", the Extremist leaders came to the conclusion that their energetic assistant, Vladimir Klostivitch, had perished by means of the explosive he had meant to employ against others. For two more hours the cutter's crew pulled steadily. At intervals the braying of fog-horns and the shrill blast of sirens told them that other water-borne traffic was under way; yet, without sighting any other craft, they held steadily on, following the edge of the ice in the still-free Morskoi Canal. Presently Captain-Lieutenant Orloff jerked the port-hand yoke-line. His keen eyes had discerned the outlines of the lighthouse on the eastern extremity of the island fortress. It was now an easy matter for the cutter to pick her way past the line of anchored destroyers. Hailed she was repeatedly; but there was no cause for alarm, since boats of the flotilla were constantly passing. Almost before Fordyce was aware of the fact the cutter was rubbing sides with R19, while leaning over the guard-rail of the submarine were the Hon. Derek and Mr. Macquare. "No, I will not stay, Monsieur le Capitan," replied Orloff in reply to Stockdale's invitation. "Later on, perhaps--who knows? Meanwhile, pray accept this gift. It is not the same as I intended to hand you, nevertheless it may be acceptable." And he indicated the enshrouded figure of the spy, Mindiggle. "Come aboard, sir," reported Fordyce as he made his way up the side. "Quite about time, Mr. Fordyce," replied the Hon. Derek, grasping his subordinate's hand. "Another hour and we should have left you behind. Confound it, what's that?" "That" was Flirt. The delighted animal, hearing her master's voice, had escaped from below, and, nearly capsizing the astonished Lieutenant-Commander, had literally bounded into the Sub's arms. CHAPTER XXIX The Captured Convoy "What do you propose to do with this, sir?" enquired Mr. Macquare, indicating the sack-enclosed form of the spy. "Goodness knows!" replied the Hon. Derek. "What is it?" "Only Mindiggle, sir," announced the Sub. "Explain yourself, Mr. Fordyce," ordered the Lieutenant-Commander.