the work was full of a real live peril, but the aerophane was cast loose at length. its upward motion was slow, perhaps owing to the denseness of the atmosphere.

for some time nobody spoke. something seemed to oppress their breathing. they were barely conscious of the faint upward motion. if they only rose perfectly straight all would be well.

"that's a fine light you had in the workshop," said eldred. "but why not have established a few hundreds of them——"

"all over london," hackness cut in. "for the simple reason that the lamp my friend lent me is the only one in existence. it is worked at a dangerous voltage too."

the upward motion continued. the sails of the aerophane rustled slightly. grimfern drew a deep breath.

"air," he gasped, "real pure fresh air! do you notice it?"

the cool sweetness of it filled their lungs. the sudden effect was almost intoxicating. a wild desire to laugh and shout and sing came over them. then gradually three human faces and a ghostly shaped aerophane emerged out of nothingness. they could see one another plainly now; they felt the upward rush; they were passing through a misty envelope that twisted and curled like live ropes. another minute and they were beyond the fog belt.

they looked at one another and laughed. all three of them were blackened and grimed and greasy, smothered from head to foot in fatty soot flakes. three more disreputable looking ruffians it would have been hard to imagine. there was something grotesque in the reflection that every londoner was the same.

it was light now, broad daylight, with a round globe of sun climbing up out of the pearly mists in the east. they revelled in the brightness and the light. below them lay the thick layers of fog that would be a shroud in earnest if nothing came to dispel it.

"we're a thousand feet above the city," eldred said presently. "we had better pay out five hundred feet of cable."

to a hook at the end of a flexible wire hackness attached a large bomb filled with a certain high explosive. through the eye of the hook another wire—an electric one—was attached. the whole thing was carefully lowered to the full extent of the cable. two anxious faces peered from the car. grimfern appeared to be playing carelessly with a polished switch spliced into the wire. but his hands were shaking.

eldred nodded. he had no words to spare just then.

grimfern's forefinger pressed the polished button, there was a snap and almost immediately a roar and a rush of air that set the aerophane rocking violently. all about them the clouds were spinning, below the foggy envelope was twisted and torn as smoke is blown away from a huge stack by a high wind.

"look," hackness yelled. "look at that!"

the brilliant light of day shone through down into london as from a gigantic skylight.

he pointed downwards. the force of the explosion had literally torn a hole in the dense foggy curtain. the brilliant light of day shone through down into london as from a gigantic skylight.

this is what the amazed inhabitants of central london saw as they rushed out of their houses after what they imagined to be a shock of earthquake. the effect was weird, wonderful, one never to be forgotten. from a radius of half a mile from st. paul's, london was flooded with brilliant light. people rubbed their eyes, unable to face the sudden and blinding glare. they gasped and thrilled with exultation as a column of fresh sweet air rushed to fill the vacuum. as yet they knew nothing of the cause. that brilliant shaft of light showed strange things. every pavement was black as ink, the fronts of the houses looked as if they had been daubed over with pitch. the roads were dark with fatty soot. on ludgate hill were dozens of vehicles from which the horses had been detached. there were numerous motor cars apparently lacking owners. a pickpocket sat in the gutter with a pile of costly trinkets about him, gems that glittered in the mud. these things had been collected before the fog grew beyond endurance. now they were about as useful to the thief as an elephant might have been.

at the end of five minutes the curtain fell again. the flying, panic-stricken pickpocket huddled down once more with a frightened curse.

but london was no longer alarmed. a passing glimpse of the aerophane had been seen, and better informed folks knew what was taking place. presently another explosion followed, tearing the curtain away over hampstead; for the next two hours the explosions continued at short intervals. there were tremendous outbursts of cheering whenever the relief came.

presently a little light seemed to be coming. ever and again it was possible for a man to see his hands before his face. above the fog banks a wrack of cloud had gathered, the aerophane was coated with a glittering mist. an hour before it had been perfectly fair overhead. then it began to rain in earnest. the constant explosions had summoned up and brought down the rain as the heavy discharge of artillery used to do in the days of the boer war.

it came down in a drenching stream that wetted the occupants of the aerophane to the skin. they did not seem to mind. the exhilaration of the fresh sweet air was still in their veins, they worked on at their bombs till the last ounce of the high explosives was exhausted.

and the rain was falling over london. wherever a hole was torn in the curtain, the rain was seen to fall—black rain as thick as ink and quite as disfiguring. the whole city wore a suit of mourning.

wherever a hole was torn in the curtain, the rain was seen to fall.

"the cloud is passing away." eldred cried. "i can see the top of st. paul's."

surely enough, the cross seemed to lift skyward. bit by bit and inch by inch the panorama of london slowly unfolded itself. despite the sooty flood—a flood gradually growing cleaner and sweeter every moment—the streets were filled with people gazing up in fascination at the aerophane.

the tumult of their cheers came upwards. it was their thanks for the forethought and scientific knowledge that had proved to be the salvation of london. as a matter of fact, the high explosives had only been the indirect means of preserving countless lives. the conjuring up of that heavy rain had been the real salvation. it had condensed the fog and beaten it down to earth in a sooty flow of water. it was a heavy, sloppy, gloomy day, such as london ever enjoys the privilege of grumbling over, but nobody grumbled now. the blessed daylight had come back, it was possible to fill the lungs with something like pure air once more, and to realise the simple delight of living.

nobody minded the rain, nobody cared an atom for the knowledge that he was a little worse and a little more grimy than the dirtiest sweep alive. what did it matter so long as everybody was alike? looking down, the trio in the aerophane could see london grow mad, grave men skipping about in the rain like school-boys at the first fall of snow.

"we had better get down," said grimfern. "otherwise we shall have an ovation ready for us, and, personally, i should prefer a breakfast. in a calm like this we need not have any difficulty in making regent's park safely."

the valve was opened and the great car dropped like a flashing bird. they saw the rush in the streets, they could hear the tramp of feet now. they dropped at length in what looked like a yelling crowd of demented hottentots.