Tom's hope was that this big blast would show such pressure in foot-tons, and give such muzzle velocity to the projectile, and at the same time such penetrating power, that he would be justified in taking it as the basis of his explosive, and using it in the big gun he intended to make.
The preliminaries had been completed. The special steel tube had been constructed, and mounted on a heavy carriage in a distant part of the Swift grounds. A section of armor plate, a foot and a half in thickness, had been set up at the proper distance. A new projectile, with a hard, penetrating point, had been made—a sort of miniature of the one Tom hoped to use in his giant cannon.
Now the young inventor and his friends were on their way to the scene of the test, taking the powder and other necessaries, including the primers, with them. Tom, Ned and Mr. Damon had some of the gauges to register the energy expended by the improvised cannon. There were charts to be filled in, and other details to be looked after.
"So General Waller won't be here?" remarked Ned, as they walked along, Tom keeping a watchful eye on Koku.
"No," was the reply. "He has gone back to Sandy Hook. He wrote that his health was bet-
