"Bless my collar button, Tom! What's going on?" asked the eccentric man, as he came up. "Has war been declared?"
"Just practicing," replied the young inventor. "Getting ready to put the armament on my aerial warship."
"Well, as long as I'm behind the guns I'm all right, I suppose?"
"Perfectly," Tom replied. "Now then, Ned, I think we'll fire."
There was a moment of inspection, to see that nothing had been forgotten, and then the big gun was discharged. There was a loud report, not as heavy, though, as Ned had expected, but there was no puff of smoke, for Tom was using smokeless powder. Only a little flash of flame was observed.
"Catch the figure, Ned!" Tom cried.
"I have it!" was the answer. "Eighty thousand!"
"Good! And I can build a recoil check that will take up to one hundred and twenty thousand pounds pressure. That ought to be margin of safety enough. Now we'll try another shot."
The echoes of the first had hardly died away before the second gun was ready for the test. That, too, was satisfactory, and then the smaller ones were operated. These were not quite so satisfactory, as the recoil developed was larger, in proportion to their size, than Tom had figured.
"But I can easily put a larger hydrostatic check on them," he said. "Now, we'll fire by batteries, and see what the total is."