"You see， the electric wires are long enough to enable him to standsome distance from the gun.And， if he likes， he can crouch behind that concrete wall of the next barbette.Still， there is some chance of an accident， for， no matter how carefully you calculate the strain of a bursting charge of powder， and how strongly you construct the breech-block to stand the strain， there is always the possibility of a flaw in the metal.So，Ned， I think we'll just go to the bomb 膒 roof ourselves， when we seeGeneral Waller making for the same place.""I suppose，" remarked Ned， "that in actual warfare anyone who fired one of the big guns would have to stand close to it--closer than that soldier is now.""Oh， yes--much，" replied Tom， as he watched General Waller giving the last instructions to the private who was to press the button."Only， of course， in war the guns will have been tested， and this one has not.Here he comes； I guess we'd better be moving."General Waller， having assured himself that everything was as right as possible， had given the last word to the private and was now making his way toward the bomb-proof， within which were gathered his fellow- officers and friends.
"You had better retire from the immediate vicinity of the gun，" said its inventor to Tom and Ned， as he passed them."For， while I have absolute confidence in my cannon， and I know that it is impossible to burst it， the concussion may be unpleasant at such close range.""Thank you，" said Tom."We are going to get in a safe place."He could not refrain from contrasting the general's manner now with what it had been at first.
As for Ned， he could not help wondering why， if the inventor had such absolute faith in his weapon， he did not fire it himself， even at the risk of a "concussion."How it happened was never accurately known， as the soldier declared positively--after he came out of the hospital--that he had not pressed the button.The theory was that the wires had become crossed， making a short circuit， which caused the gun to go off prematurely.
But suddenly， while Tom， Ned and General Waller were still some distance away from the bomb-proof， there was a terrific explosion.Itseemed as if the very foundations of the fortifications would be shattered There was a roaring in the air --a hot burst of flame， and instantly such a vacuum was created that Tom and Ned found themselves gasping for breath.
Dazed， shaken in every bone， with their muscles sore， they picked themselves up from the ground， along which they had been blown with great force in the direction of the bomb-proof.Even as Tom struggled to his feet， intending to run to safety in fear of other explosions， he realized what had happened.
"What--what was it？" cried Ned， as he， too， arose."The gun burst！" yelled Tom.
He looked to the left and saw General Waller picking himself up， his uniform torn， and blood streaming from a cut on his face.At the same instant Tom was aware of the body of a man flying through the air toward a distant grass plot， and the young inventor recognized it as that of the soldier who had been detailed to fire the great cannon.
Almost instantaneously as everything happened， Tom was aware of noticing several things， as though they took place in sequence.He looked toward where the gun had stood.It was in ruins.The young inventor saw something， which he took to be the projectile， skimming across the sea waves， and he had a fleeting glimpse of the greater portion of the immense weapon itself sinking into the depths of the ocean.
Then， coming down from a great height in the air， he saw a dark object.It was another piece of the cannon that had been hurled skyward.
"Look out！" Tom yelled， instinctively， as he staggered toward the bomb-proof， Ned following.
He saw a number of officers running out to assist General Waller， who seemed too dazed to move.Many of them had torn uniforms， and not a few were bleeding from their injuries.Then the air seemed filled with arain of small missiles 膕 tones， dirt， gravel and pieces of metal.
