were below in
the refrigerators. Simon let the cylinder fall on to a slab; Albert
turned a tap, and immediately the cylinder was surrounded by clouds of
steam. The phenomenon was like some alchemical and mysterious operation.
And the steam, as it rose and spread abroad in the immense, pale
interior, might have been the fumes of a fatal philtre distilled by a
mediaeval sorcerer.

'I hope it won't blow up!' Simon ejaculated.

'Not it!' said Albert. 'Let's have a look at it now.'

Albert had a mechanical bent, and, with the aid of a tool, he soon
discovered that the cylinder was divided into two parts. In the lower
part was burning charcoal. In the upper, carefully closed, was paraffin.
The division between the two compartments consisted of some sort of
soldering lead, which the heat of the charcoal had gradually been
melting.

'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 Al