"Whew! That was a lucky escape," murmured Tom, as he sat down on one of the boxes, and wiped the smoke and sweat from his face."A little later and there'd only been a hole in the ground to tell what happened.hot work; eh, Ned?""I guess yes, Tom."
"I thought of the powder as soon as I saw that the truck was on fire," explained the expressman; "but I didn't know what to do.I was kinder flustered, I guess.This is the second time this old truck has caught fire from a leaky gasoline pipe.I guess that will be the last--it will for me, anyhow.I'll resign if they don't give me another machine.Will you sign for your stuff?" he asked Tom, holding out the receipt book, which had escaped the flames.
"Yes, and I'm mighty glad I'm here to sign for it," replied the young inventor."Now, Koku, I guess you can take that stuff up to the shop; but be careful where you put it.""I do, Master," replied the giant.
"What sort of powder is that, Tom?" asked Ned a little later, when they were again back in the office, the excitement having calmed down.The expressman had gone back to town afoot, to arrange about getting another vehicle for what remained of his load."Is it the kind they use in big guns?" "One of the kinds," replied Tom."I sent for several samples, and this is one.I'm going to conduct some tests to see what kind I'll need for my own big gun.But I expect I'll have to invent an explosive as well as a cannon, for I want the most powerful I can get.Want to look at some of thispowder?"
"Yes, if you think it's safe."
"Oh, it's safe enough if you treat it right.I'll show you," and working carefully Tom soon had one of the boxes open.Reaching into the depths he held up a handful of something that looked like sticks of macaroni."There it is," he said.
"That powder?" cried Ned."That's a queer kind.I've seen the kind they use in some guns on the battleships.That powder was in hexagonal form, about two inches across, and had a hole in the centre.It was coloredbrown."
"Well, powder is made in many forms," explained Tom."A person who has only seen black gunpowder, with its little grains, would not believe that this was one grain of the new powder.""That macaroni stick a grain of powder?" cried Ned.
"Yes, we'll call it a grain," went on the young inventor, "just as the brown, hexagonal cube you saw was a grain.You see, Ned, the idea is to explode all the powder at once--to get instantaneous action.It must all burn up at once as soon as it is detonated, or set off.
"To do that you have to have every grain acted on at the same moment, and that could not be done if the powder was in one solid chunk, or closely packed.For that reason they make it in different shapes, so it will lie loose in the firing chamber, just as a lot of jack-straws are piled up.In fact, some of the new powder looks like jack-straws.Some, as this, for instance, looks like macaroni.Other is in cubes, and some in long strings."As he spoke Tom struck a match and held the flames near the end of one of the "macaroni" sticks.
"Caesar's grandmother!" yelled Ned."Are you crazy, Tom?" as he started to leap for a window.
"Don't get excited," spoke Tom, quietly."There's no danger," and he actually set fire to the stick of queer powder, which burned like some wax taper.
"But--but--" stammered Ned.
"It is only when powder is confined that it explodes," Tom explained."If it can burn in the open it's as harmless as water, provided you don't burn too much at once.But put it in something where the resulting gases accumulate and can't escape, and then-- why, you have an explosion--that's all.""Yes--that's all," remarked Ned, grimly, as he nervously watched the burning stick of powder.Tom let it flame for a few seconds, and then calmly blew it out.
"You know what a little puff black gunpowder gives, if you burn some openly on the ground," went on Tom; "don't you, Ned?""Sure, I've often done that."
"But put that same powder in a tight box, and set fire to it, and you have a bang instead of a puff.It's the same way with this powder, only it doesn't even puff, for it burns more slowly.
"An explosion, you see, is the sudden liberation at one time of the gases which result when the powder is burned.If the gases are given off gradually, and in the open, no harm is done.But put a stick like this in, say, a steel box, all closed up, save a hole for the fuse, and what do you have? An explosion.That's the principle of all guns and cannon.
"But say, Ned, I'm getting to be a regular lecturer.I didn't know I was running on so.Why didn't you stop me?""Because I was interested.Go on, tell me some more.""Not now.I want to get this powder in a safe place.I'm a little nervous about it after that fire.You see if it had caught, when tightly packed in the boxes, there would have been a terrific explosion, though it does burn so harmlessly in the open air.Now let me see--"Tom was interrupted by the postman's whistle, and a little later Eradicate came in with the mail that had been left in the box at the shop door.Tom rapidly looked over the letters.
"Here's the note I want, I think," he said, Selecting one."Yes, this is it.'Permission is hereby granted,' he read, 'to Thomas Swift to visit,' and so on, and so on.This is the stuff, Ned!" he cried.
"What is it?"
"A permit to visit the government proving grounds at Sandy Hook, Ned, and see 'em test that new big gun I was telling you about.Hurray! We'll go down there, and I'll see how my ideas fit in with those of the government's experts.""Did you say 'we' would go down, Tom?" "I sure did.You'll go with me; won't you?""Well, I hadn't thought very much about it, but I guess I will.When isit?"
"A week from today, and I'm going to need all that time to get ready.
Now let's get busy, and we'll arrange to go to Sandy Hook.I've had trouble enough to get this permit--I guess I'll put it where it won't get lost," and he locked it in a secret drawer of his desk.
Then the lads stored the powder in a safe place, and soon were busy about several matters in the shop.
