"Certainly it is for me," admitted the Russian. "But surely, Monsieur, you have handled this precious parcel very carelessly? Are you not aware that diamonds greatly deteriorate if exposed to low temperatures?" "Hanged if I am," declared Fordyce. "I was certainly not warned to that effect. But, look here----" Klostivitch held up a warning finger. "No harm has apparently been done," he remarked. "In any case, a brief examination of the diamonds will confirm my belief. If you will come with me to my testing laboratory we will make a joint investigation." Again Fordyce hesitated. He was doubtful whether to tackle the man straight away or to wait until the Russian himself made the discovery that the packet contained nothing but broken glass. The mere fact that the Extremist had finally accepted the statement that the "diamonds" were for him was sufficient proof that he was in league with a dangerous secret society in Great Britain. Cornered and threatened, he would be pretty certain to give the names of his accomplices and the formula of the ingredients from which the deadly nitro-talcite was compounded. The fellow might raise a terrific commotion afterwards, Fordyce reflected, but the Sub was prepared to risk that. Once he and the petty officer were clear they would discard their disguise and appear in their true characters as members of Submarine R19's complement. In any case, they could take efficient steps to prevent Vladimir Klostivitch raising an alarm until several hours had elapsed. "All right; lead the way, monsieur," he exclaimed. The old man opened the door of the stove and thrust a strip of wood into the glowing furnace. With this he lighted a cast-iron oil lamp. "My laboratory is below the ground," he explained, "and owing to the scarcity of candles, and the failure of the authorities to maintain the supply of electric light, I am compelled to fall back upon this lamp. It will be quite enough for the brief examination I propose to make. Follow me, if you please." Crossing the stone floor, Klostivitch threw back a thick, faded curtain that hitherto concealed a doorway under the broad staircase. A rush of warm air swept from the gloomy opening. In spite of the otherwise cheerless conditions, the house in Bobbinsky Prospekt was well heated, even the cellars. "Be careful," cautioned the guide as he preceded his guests and held the lamp low in order that its feeble rays might illuminate the worn stone steps. "It is not often that visitors honour my laboratory with their presence, otherwise I might have devoted a more accessible place to my researches." "It is quite all right," rejoined Fordyce. "At any rate," he soliloquized, "you are in front of me, so it will go hard with you if you try any low-down tricks."