Chapter 7

     “Crud,” Strufis groaned as the three caught up to them. In front of them was a broad, deep river, with no bridge in sight. “We can’t go around this, this river flows across the entire landscape…and the nearest bridge is miles away…”
     Behind them, they started to hear distant voices, and a stray arrow hit one of the trees nearby.
     “If we swim, we’ll be sitting ducks,” Phillip growled, grimacing.
     “Not if we’re swimming, we wouldn’t,” Anastasia remarked.
     “Haha. Almost forgot to laugh.”
     “I’m trying to think,” Strufis mumbled, fumbling through his knapsack. “What can make a river disappear? Or make it so we can cross quickly?”
     Drew scratched his head. “Is there some way we can walk across it? Or – hey, can we try to freeze it? Like in Legend of Zelda with the freeze arrow!”
     “Freeze? I only have chemicals and salts in here, not a freezer…”
     “Wait!” Heather started with realization. “Do you have that ammonium…ammonium…grah, I can’t remember the last part…it’s the chemical that they use in instant ice packs…!”
     Drew pondered. “Isn’t that ammonium nitrate?”
     “That’s it, that’s it!!”
     “Ammonium nitrate?” Strufis exclaimed. “Of course! It’s greatly endothermic, so much it freezes water almost instantly. Dang, I should have thought of that. Let me dig it out…c’mon, where is it…”
     Heather frowned. “But that only does a small amount of water in a bag. How it the world is it going to do a entire river-”
     Strufis yanked out a vial with some white powder in it. “Got it!!”
     He tossed some of the powder into the water, and when it touched the surface, the water instantly froze, and in seconds, the ice spread across the banks and both up and down stream. As they watched, it thickened with a crackling sound.
     Strufis held out a foot and stomped on the ice. It thudded solidly. He stepped on it, and the ice didn’t budge. “Okay, I think it’s done. Hurry up, they’ll catch up to us any minute!”
     With a bit of trepidation, the four gingerly stepped onto the ice. Drew almost slipped as he stepped onto the surface. However, the ice was steady.

They hurried across the river towards the far bank, trying not to slip and fall.
     “How could a little amount freeze that much water so strongly?” Heather asked in bewilderment. “No way could that small amount do that much in our world…”
     “Well, like I figured before, in your world the reactions are more mundane compared to ours,” Strufis replied. “Although the same rules apply, evidently.”
     They reached the other side and glanced back. They saw people coming through the trees, only enough to see their silhouettes but were moving fast enough to reach them in less than a minute.
     “Quick! We need to melt this ice!” Drew exclaimed. “Otherwise they’ll just follow us across!”
     “How? We don’t have time to mix together an exothermic reaction that’ll melt it fast enough!”
     “Hey. Don’t you remember how to lower the freezing point of water?” Phillip reminded them gruffly.
     “Oh yeah…hey, you got any aluminum nitrate in there? Or calcium chloride? Anything that has a van Hoff factor bigger than two!”
     “Got calcium chloride right here; it’s highly exothermic, it’ll melt the ice even faster. Here it goes!” Strufis threw the salt onto the ice just as the first of the pursuers on the other side reached the clearing. They looked as if they had stepped out of Robin Hood of Sherwood Forest; their homespun cotton and woolen clothing, along with their leather straps and equipment almost made the group forget that just a little while ago they had been in a densely populated, modernized city.
     Before those on the other side could reach the frozen river, the salt already had made the ice get moist and thin. By the time they reached the banks the last of the ice had drifted to the center of the river and melted away.
     “Hah!” Drew hollered triumphantly, smirking at the men at the other side. “Chemical Geniuses 1, Forest Hobos 0!”
     An archer on the other side pulled out an arrow and shot at him. Drew had to dive aside in a panic. “Whoa! Sorry, dude! Robin Hood is cool! Really!”
     “All right, let’s clear out,” Heather yelled.
     After checking to see that everyone was all right, they hurried back into the trees.