She could hear a hard sound, as of metal being filed down, and more than once distinguished the clinking of glass, as though her father was engaged in some experiment with his test-tubes and other scientific paraphernalia which she had seen arranged so methodically upon the two long deal tables. "What has Ortmann told you?" asked Theodore Drost's midnight visitor, while his daughter stood back within the long cupboard on the landing, listening. "He says that all is in order. We have a friend awaiting us." "And the payment--eh?" asked the man Nystrom, a German who had been naturalised as a Swede, and now lived in London as a neutral. As a professor of chemistry he had been well-known in Stockholm and, being a bosom friend of the Dutch pastor's, the pair often delighted in dabbling together in their favourite science. "I shall meet Ernst on Friday night. If we are successful, he will pay two thousand pounds--to be equally divided between us." "Good," grunted the other. "We shall be successful, never fear--that is if Ortmann has arranged things at his end. _Himmel_! what a shock it will be--eh, my friend?--worse than the Zeppelins!" Theodore Drost laughed gleefully, while his daughter, daring to creep forward again, peered through the crack of the door and saw the pair bending over what looked like a square steel despatch-box standing upon the table amid all the scientific apparatus. The box, about eighteen inches long, a foot wide, and six inches deep, was khaki-covered, and, though she was not aware of it at the time, it was of the exact type used in the Government offices. Fridtjof Nystrom, a tall, dark-haired man, with a red, blotchy face, rather narrow-eyed and round-shouldered, was adjusting something within the box, while old Drost, who had discarded his shabby black pastor's coat and now wore a dark-brown jacket, took up a small glass retort beneath which the blue flame of a spirit-lamp had been burning, and from it he poured a few drops of some bright red liquid into a tiny tube of very thin glass. Then, taking a small blow-pipe, he blew the flame upon the tube until he had melted the glass and sealed it hermetically. The blotchy-faced man watched this latter operation with great interest, saying: "Have a care now, my dear Theodore. The least mishap, and not a piece of either of us would remain to tell the story." "_Ja_! Leave that to me," answered Ella's father. "We do not, I agree, desire a repetition of the disaster which happened last week." Ella, hearing those words, stood aghast.