"_Now!_" he ejaculated, as he suddenly pulled the lever, and for the last time sent forth the automatic shower of destructive shells. A second later there was a bright flash from above as if the sun itself had burst, and then came a most terrific explosion, which caused the earth to tremble where they stood. The clouds were rent asunder by the frightful detonation, and down upon the Russian camp the débris of their ingenious invention fell in a terrible death-dealing shower. The annihilation of the dastardly plot to wreck the city was complete. Small dynamite shells from Mackenzie's pneumatic gun had struck the car of the balloon, and by the firing of half a ton of explosives the enemy was in an instant hoist with his own petard. As the débris fell within the Russian lines, some fifty or sixty picric-acid bombs--awful engines of destruction--which had not been exploded in mid-air, crashed into the Muscovite ranks, and, bursting, killed and wounded hundreds of infantrymen and half a regiment of Cossacks. One, bursting in the enemy's headquarters, seriously injured several members of the staff; while another, falling among the Engineers' transport, exploded a great quantity of gun-cotton, which in its turn killed a number of men and horses. The disaster was awful in its suddenness, appalling in its completeness. The aëronauts, totally unprepared for such an attack, had been blown to atoms just when within an ace of success. Fortune had favoured Britain, and, thanks to Mackenzie's vigilance and his pneumatic dynamite gun, which the Government had rejected as a worthless weapon, the grey old city of Edinburgh was still safe. But both Russians and Britons had now mustered their forces, and this, the first note sounded of a second terrific and desperately-fought battle, portended success for Britain's gallant army.