'So when this stuff had melted,' he explained to Simon, 'the paraffin would run into the charcoal, and there would be a magnificent flare-up.' They looked at one another, amazed, astounded, speechless. And each knew that on the tip of the other's tongue, unuttered, was the word 'Ravengar.' 'But why was it put in the lift?' asked Simon. 'Because,' said Albert promptly, 'a lift-well is the finest possible place for a fire. There's a natural draught, and a free chance for every floor. Poof! And a flame's up nine stories in no time. And a really good mahogany lift would burn gorgeously, and give everything a good start.' 'There are fifteen lifts in this place,' Simon muttered. 'I know,' said Albert. He approached a little glass square in the wall, broke it, pulled a knob, and looked at his watch. 'We'll test the Fire Brigade Department,' he remarked; and then, as he heard a man running down the adjacent corridor, 'Seven seconds. Not bad.' In another seven minutes nine cylinders, which had been found in nine different lifts, were sizzling beside Albert's original discovery. The other five lifts appeared to have been omitted from this colossal scheme for providing London with a pyrotechnic display such as London had probably never had since the year 1666. The night fire staff, which consisted of some fifty men, had laid hose on to every hydrant, and were taking instructions from their chief for the incessant patrol of the galleries. 'See here,' said Albert, 'we'd better go on with what we started of now.' 'Had we?' Simon questioned somewhat dubiously. 'Of course,' said Albert. 'If that is Ravengar in the photo, and if we can find out anything to-night, and if Ravengar's in this business'--he jerked his elbow towards the cylinders--'we shall be so much to the good. Besides, it won't take us a minute.' So they went forward, through twilit chambers and passages filled with sheeted objects, past miles of counters inhabited by thousands of chairs, through doors whose openings resounded strangely in the vast nocturnal silence of Hugo's, till they came to the Medical and Pharmaceutical Department. And the Medical and Pharmaceutical Department, in its night-garb, and illuminated by a single jet at either end of it, seemed to take on a kind of ghostly and scented elegance; it seemed to be a lunar palace of bizarre perfumes and crystal magics. The two young men halted, and listened, and they could catch the distant footfall of the patrols echoing in some far-off corridor. That reassured them. They ceased to fancy the smell of burning and to be victimized by the illusion that a little tongue of flame darted out behind them. Albert gained access to the accountant's cupboard, and pulled out a number of books, over which they pored side by side. 'Here you are!' exclaimed Simon presently. 'Receipts. January 9.'