Lawsuit against MIT kids for dropping block of sodium in Charles that injured five quietly settled

I thought sodium disintegrated after a short while in the water?

My chemistry professor used to chuck smaller pieces of sodium across a lake. Kind of like skipping stones, but a LOT more fun. The pieces would disappear after just a minute or two. I get that these were larger 'blocks' but I'm surprised they last that long in the river.

from
http://www.amazon.com/Novel-Efficient-Synthesis-Ca...

Nozick pulled the cardboard box toward him. "I said that the time has come for all good men." And he opened the box and lifted out the mysterious Pyrex dumbbell.
They had made some modifications to it. Although its true functional nature was not known, they had adapted it to this, its end use. Nozick and Laura had washed it out with soapy water, then rinsed it with ethanol and dried it with a heat gun. Under a nitrogen atmosphere, they had with great care and respect filled the inner of the glass sleeves with molten potassium metal that had ran silver as mercury into its new home and slowly resolidified to fit its new abode. Laura had felt something like a priest of ancient Egypt ritually preparing a body for mummification. Except that mummies were tarred up to last for eternity, and the Pyrex corpse was fitted with a quite reactive metal which wanted only a drop of the good Charles to initiate its fiery passage to the afterlife.
Nozick held the offering in both hands, away from his body, exactly horizontal, a holy man with one of his relics. The silvery surface of the potassium was more perfect than the best mirror. It reflected the stars, the city lights silver and blinking red, their dim faces in a strangely wonderful elongated fisheye lens. The effect was of a timeless perfection, which it was - in a metamorphic way. Nozick had long before brought some of this very potassium up from the subsubbasement chemical morgue because he liked the way it looked. It had been formed in short stubby cylinders packed into its protective oil bath like metallic kosher dills, in a slightly amber gallon jar, with a tin and wax seal on the top and a yellowed, hand-written label clinging to the side. It was not dated. It could have been manufactured in 1950 or 1850. Even 1750 was not out of the question.
Now they were standing as far out into the river as they could on three flat-topped ebony rocks that formed a little natural jetty. Nozick handed the cylinder to Laura with great solemnity. "Madame, would you be so kind?"
Laura took the loaded glassware gingerly. She bounced it lightly, testing its weight, judging the thrust necessary to heave it out as far as she could without causing her to go all Third Law backwards off of the rock.
"We commend to the deep this thingy," Nozick boomed out in some kind of accent he probably thought to be a facsimile of James Mason. "It was a good thingy...though we knew not what it did."
"It's commit to the deep, not commend to the deep," Laura said.
"Whatever it is," Nozick declared, still in character. "Better this watery grave, a quick merciful end in the hope that it will someday be resurrected in Paradise than to be taken to the pit of Hell itself by the lying thieving son-of-a-demon whose name decent men dare not speak."
"Amen." Laura wound up and slung her charge up into the night sky.
For a long moment they lost it, she had managed to toss it so far. Then it hit the formless water, and they saw it spinning its way beneath the surface.
Nothing happened, but they did not breathe. Laura had plugged the nipple inlets, the small channels the water would have to enter to encounter the potassium, with tight plugs of Kimwipe tissue. The water would work its way through, eventually, but how long that might be they did not know. It was an experiment, the first and most probably last of its kind. Their only fear was that the tissue would prove so unexpectedly water resistant and the cylinder so dense that it would sink to the bottom of the Charles and stay there until dawn came to chase them home. Then it might rise up like an ancient mine from a forgotten war and scare the hell and bejeesus out of the Harvard lads rowing by in their coxed eights.
Laura let out her breath and was just about to ask Nozick for reassurance when she saw a light beneath the water. It was a point, possessing no width or length or apparent depth, that glissandoed into the visible spectrum from some ultraviolet starting place and was now hovering in the blue, teetering on green.
I love chemistry for that, she thought. Bringing these things into contact that would be otherwise forever happy alone, never knowing their potential for change. Gathering complex molecules from the world, sequestering them from light, oxygen, heat, and water in an inert solvent until their irresistible urge to diffuse drives them into the influence sphere of the others in solution and the kinetic and thermodynamic inevitabilities begin. Change. There was nothing more delicious than creating a new molecule never before known on the planet and probably never in the whole of this universe, and navigating that journey from known to novel with nothing but your thoughts and a few milliliters of anhydrous tetrahydrofuran.
Nozick was behind her to the left, and she was turning her head to see what his face would tell her when he seized the whole of the back of her shirt and yanked her. They flew together onto their backs just as a billowing dragon’s breath cloud exploded amber over them, illuminated for an booming instant both sides of the river, cars, goals, trees, buildings, and them, then was gone back into pitch black even darker than before for the sudden destruction of their night vision.
Nozick sat up. On the river, several dozen hissing, popping demons flew randomly about on the surface: chartreuse, ivory, and turquoise by turns. They flickered out one by one until the night was reestablished.
Laura's pulse was thundering in her ears, and she found that she was panting. She stood up and looked around. No cars had stopped. No sirens. No one running to see what was the matter with the suddenly detonating Charles.
Nozick walked back out onto the stones and looked down into the water. "You know what I hate about chemistry?" he said. "Doing something totally amazing in chemistry is like pissing your pants in a dark suit. You get a warm feeling but nobody else notices."