‘Conf—!’ he exclaimed, dropping it sharply.  ’It’s hot.  What in the name of—­’

He kicked the object out of the lift on to the tessellated floor of a passage which led to the Fish and Game Department.

‘I bet you I can hold it,’ said Simon boastfully.

And, at the expense of his fingers, he picked it up, and successfully carried it into the Fish and Game Department, where a solitary light (which burnt night and day) threw a dim radiance over vast surfaces of white marble dominated by silver taps.  The fish and game 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.